Dönitz was even more wary of Sweden than Raeder. When he assumed command of the navy in January 1943 Hitler wanted him to scrap the surface fleet, but Dönitz pointed out that powerful German naval forces in the Baltic would help influence Sweden’s attitude. A major irritant to Dönitz was the activity of Swedish aircraft in the Baltic. On several occasions German warships reported being “buzzed” by Swedish planes. In July 1943 the Skl ordered German vessels to open fire if approached by Swedish aircraft, maintaining that the Swedes repeatedly had been requested through diplomatic channels to halt this activity. The next month, following another incident of this type when Swedish aircraft shadowed a German convoy, Schmundt (Naval High Command, Baltic) complained that the Swedes would certainly pass any information on to Germany’s enemies. Schmundt regarded the Swedes with great mistrust; in fact, he counted them as already in the enemy camp. In August 1943 he warned the Skl that Swedish shipping represented a sizeable reserve for the Anglo-Americans. Noting Sweden’s increasingly hostile stance, he insisted that Germany must prevent the enemy’s use of these vessels. Schmundt proposed sending commandos to destroy ships in Swedish ports. Apparently the Skl considered this suggestion too far-fetched and an invitation for trouble.
The navy’s problems with Sweden persisted. Swedish fishing boats on at least two occasions entered a forbidden area and sabotaged lights on German buoys. In retaliation the Germans sank two Swedish fishing boats in the area in August 1943. Following this altercation the Foreign Ministry instructed the Skl to avoid further incidents with Sweden. Yet cases of “buzzing” and violations of German airspace continued, until events came to a head on 14 May 1944, when a German fighter shot down a Swedish plane near Libau. At first Kummetz (Schmundt’s successor) assumed that it had been a Soviet plane with Swedish markings, but he suspiciously added that if it were Swedish, it was spying on German U-boat training areas for Britain or Russia. Kummetz soon received a report that three Swedish air-men had been picked up in a dinghy, and early the next day the Germans shot down a second Swedish plane near Windau. Kummetz declared that Sweden and Germany’s enemies alike recognized the importance of air reconnaissance over this part of the Baltic and that the extraordinary search and rescue operation the Swedes had mounted when their plane had been downed revealed the importance of this information.
Kummetz’s problems with the Swedes were not yet over. At the beginning of July a German patrol boat spotted a Swedish destroyer. Swedish aircraft had not reappeared over the coast of the Baltic States, but, Kummetz argued, now destroyers had taken their place. Within a month the Germans sighted Swedish warships near the Irben Straits on three occasions. A German patrol boat near Moen fired on a Swedish plane after it approached to a distance of nine hundred meters. To the Germans’ utter surprise, the aircraft returned fire! Perplexed, Kummetz remarked that this was the first instance of Swedish aircraft fighting back. Finally, less than a week after that incident a U-boat training flotilla reported encountering a Swedish destroyer eighteen nautical miles north-northwest of Libau. Stunned, Kummetz exclaimed, “The Swedes are in the middle of our U-boat training area!”
Although regarded with great suspicion by the Germans, especially Schmundt and Kummetz, Swedish air and naval reconnaissance in the Baltic had been carried out for defensive purposes. The Swedes periodically worried about a German attack, either because the government was about to announce a measure displeasing to the Germans or because intelligence warned of an imminent German invasion. For example, on 28 July 1943, a few days before Sweden canceled the transit agreement, the Swedes began to carry out secret reconnaissance flights from the Kalmar Sound to the area near the island of Bornholm. As a further precaution, naval vessels laid mines along Sweden’s southeastern coast. In the first week of August the Swedes supplemented their air reconnaissance with patrols by destroyers near the island of Gotland and off the southeastern coast. Another invasion scare occurred at the end of March 1944, as a result of deteriorating relations between Finland and Germany. Sweden attempted to arrange peace talks between the Soviets and the Finns, angering Germany. The Swedes stepped up their air reconnaissance, and on 14 May a plane failed to return. The following day a minesweeper hailed a Latvian fishing boat and learned that the plane had been shot down. On 16 May Sweden’s Naval Staff ordered reconnaissance in this area halted. The Swedish airplane had been sent to search for transports at sea or around ports in the Baltic States, an area where the Swedes’ intelligence was poor. It had merely been a case of mutual suspicion.
Nazi preparations to seize the Åland Islands, “Tanne West,” began in the spring of 1944 and brought Sweden under even closer scrutiny. In July Kummetz warned of the possibility that Sweden might seize the islands itself. When the Germans sent heavy warships to aid Finland in the summer of 1944, the Skl instructed them to remain beyond the previously envisioned time, due to the unfavorable situation in the Gulf of Finland and also in consideration of Sweden. Although an announcement informing Sweden of Germany’s reasons for seizing the Åland Islands had been prepared, Hitler decided to cancel the operation out of regard for Sweden. In early 1944, as Sweden arranged peace talks between the Soviets and the Finns, concern for a German invasion of the Åland Islands, and possibly of Sweden itself, became acute, and the Swedes considered occupying the islands themselves. From the end of March until mid-April Swedish preparations for war steadily increased. After the Soviet summer offensive in Karelia the Swedes again briefly fretted about a German attempt to seize the Åland Islands. When word of the Germans’ unsuccessful attempt to seize Hogland arrived, the Swedes stepped up their reconnaissance near the Åland Islands but ordered no overall change in defensive readiness.
The string of Allied victories in the summer of 1944 convinced the Swedes that Hitler would lose the war and that it would be advisable for Sweden to distance itself from Germany. In the second half of that year the Swedes dealt the Germans a series of economic blows. In August, Sweden’s government announced that it would no longer insure shipping to German ports, in effect forbidding its vessels to sail to Germany. The government halted the last transit through its territory on 9 September. On 27 September, fearful that Soviet submarines would soon reach the Baltic, Sweden closed its Baltic ports and territorial waters to all foreign shipping. Finally, on 12 October the Swedes ended the export of ball bearings to Germany. All of these measures were serious, but the withdrawal of Swedish shipping was most damaging, because from 1941 to 1944 Swedish vessels had brought an average of at least 40 percent of the iron ore to Germany, and Finnish vessels nearly 10 percent. With Finland out of the war and Swedish shipping to Germany halted, the Nazis faced the loss of half of the vessels engaged in transporting ore to the Reich. The closure of Sweden’s ports also meant that iron ore, even if Germany could scrape together ships to transport it, had to travel the long, dangerous route from Narvik. These events sobered the Skl, which on 29 September issued a directive to avoid all violations of Swedish territorial waters. In view of the current political tension with Sweden, that nation could be given no excuses for going over to the enemy side.
Yet the German Navy was furious over these measures. The Skl viewed Sweden’s actions as proof that it had submitted to Allied demands to halt ore deliveries to the Reich. Dönitz declared that the Swedes had taken these steps because of “fear and dependence on international Jewish capital.” He added that Germany could still fight without Swedish ore and that the Swedes had best beware. On several occasions in the latter part of 1944 the Skl insisted that it must retain its heavy surface vessels not only to engage the Soviet fleet but with regard to Sweden as well. At the beginning of October the navy proposed the erection of launchers for Germany’s unmanned rockets to threaten cities in southern Sweden, but on 15 October Keitel announced that it was in Germany’s interest to avoid incidents with Sweden.
At the beginning of October 1944, Soviet submarines entered the Baltic. In response to this the Skl wanted to declare the entire eastern Baltic, including the Gulf of Bothnia, an operational zone. Kummetz was clearly still angry about Swedish incursions in the area during the summer. He claimed that militarily it was unnecessary to include the Gulf of Bothnia and Åland Sea but that the declaration of the eastern Baltic as an operational zone made it possible to sink all merchant ships without regard to their nationality, and Swedish warships and aircraft in the area would be fair game. Kummetz also pointed out that mines would be effective in disrupting shipping between Sweden and Finland. Dönitz replied that the navy had no interest in traffic between Finland and Sweden. After the official declaration of the eastern Baltic as a war zone as of 11 November, the Skl repeatedly instructed U-boats to fire only if they were certain the target was not a Swedish vessel.
At the beginning of 1945, OKW considered a report from the military attaché in Stockholm that warned of Sweden’s entering the war, and it returned to the proposal of erecting launching pads for V-1 and V-2 rockets pointing toward Stockholm. The Germans believed that this would dampen any enthusiasm for war in Sweden. But a few days later Hitler decided that Sweden’s entry into the war was unlikely and that no preparatory measures for Swedish belligerence should be taken. In mid-February OKW noted that relations with Sweden had further deteriorated, citing a report from the German military attaché in Sweden, Bruno von Uthmann, describing Sweden’s attitude as “unsettling.” Hitler too viewed Sweden with increased suspicion. In March he refused a proposal to evacuate northern Norway because he feared it would provide an incentive for Sweden to enter the war if the Anglo-Americans seized Narvik and established a link with Sweden. The presence of Norwegian “police troops” in Sweden was another cause of concern.
The German Navy also drew up plans for an invasion of Sweden and reviewed them regularly. The navy first examined a landing operation on Sweden’s coast around the turn of the year 1939–40. This study, however, was only theoretical and does not appear to have been linked with plans to invade Norway and Denmark then under consideration. In the spring of 1943 the navy again analyzed the possibility of attacking Sweden. In this study the Skl asserted that the seizure of Sweden’s fleet would considerably strengthen Germany’s navy. The Skl also declared that Sweden’s navy represented a “considerable threat,” due to the lack of German escort vessels and the decisive importance of the Baltic for Germany. Indicating that it could not destroy the Swedish Navy, the Skl explained that the elimination of Sweden’s fleet required the German Army to capture its ports by land, which it should do as quickly as possible. But the Skl expressed grave reservations about the entire scheme. War with Sweden would reduce, if not paralyze, U-boat training in the Baltic; disrupt supply shipments to Finland, the Baltic States, and Norway, as well as the delivery of ore imports; and end the transit traffic to Norway. If Sweden and its ports could be occupied within days or even a few weeks, the navy considered the operation worthwhile. But if the Swedes continued longer to hold parts of their country, it could invite disaster. This would serve as an invitation for the Allies to invade Scandinavia and base aircraft in Sweden, which would endanger the Baltic—and loss of the U-boat training areas in the Baltic signified the death of the U-boat war. The Skl concluded that action against Sweden without a compelling reason was justifiable only if the success of the operation within a very short time was guaranteed. In view of Germany’s current situation, this was quite unlikely.
The navy, therefore, did not recommend the invasion of Sweden. The reason was that at the end of March 1943 the Skl had considered the repercussions of an Allied invasion in northern Norway. Although the Skl feared an undesirable effect upon the attitude of both Finland and Sweden, it regarded an Allied presence in Sweden as the greatest danger. In the Skl’s eyes Sweden would serve as a bridge to the Baltic, whereas the continuation of the U-boat war required Germany’s absolute control of the Baltic. In October 1943 the question of war with Sweden again surfaced. Meisel claimed that political developments, presumably Sweden’s halt to the transit traffic, raised the possibility of Sweden’s declaring war on Germany. He ordered a reexamination of the May study, based on the assumption of Swedish belligerence due to an Allied landing in Norway, Jutland, or western Sweden. Schmundt looked into this matter, but his assessment was no brighter than the previous one. He warned that the greatest danger from war with Sweden would be the Allies’ immediate use of Sweden as an air base. This would necessitate a vast increase in air defense for all ports and important bases in the central and eastern Baltic, as well as the Gulf of Riga and Gulf of Finland. Furthermore, the mere threat of Swedish submarine activity would require the formation of antisubmarine flotillas and the gathering of escorts for supply transports to Finland, the Baltic States, and Norway. Ending on a most discouraging note, Schmundt pointed out that one could draw parallels to the situation in the Mediterranean, especially the struggle to retain North Africa. Another report on this subject from Naval High Command, Norway, reached similar conclusions.
Following the numerous steps the Swedish government took to throttle trade with Germany in the fall of 1944, the possibility of Sweden’s belligerence arose once more in mid-October. Meisel requested Wagner and the Skl’s operations section jointly to examine the consequences of war with Sweden. An Skl report from the same day noted that several problems raised in the 1943 study, such as supply of Finland and loss of imports from Sweden, no longer had any bearing on the situation. The loss of U-boat bases on France’s Atlantic coast, however, had increased the importance of control of the Baltic entrances and sea routes to Norway. The greatest problem facing Germany in the execution of such an operation was that there simply were no ground or air forces available to fight Sweden. For this reason, Germany had endeavored to keep Sweden neutral and avoid incidents. On 29 October this latest study, bearing Wagner’s signature, was completed. In it he claimed that the most effective way to eliminate the dangers resulting from Sweden’s belligerence would be to conquer and occupy the country, at least its southern half, either as a preventive measure or immediately after Sweden declared war. Wagner, however, realized that there was no chance of obtaining forces to attack Sweden. If Sweden entered the war it would almost certainly coordinate an attack of its own on Norway, probably toward the Oslo–Bergen area or Trondheim, with an Allied landing. One of Wagner’s greatest concerns was that Germany’s sea routes and U-boat training areas lay open between the German and Swedish coast. Wagner did not present a particularly optimistic assessment either.
At the beginning of December Dönitz stressed that the question of whether or not Sweden entered the war was of the utmost importance. He insisted that the disadvantages would be so serious as to outweigh any possible gains. Dönitz explained that he had informed Keitel and Ribbentrop of his views on this subject. On 9 February 1945, at the Skl’s request, Jodl issued instructions to Germany’s armed forces that Sweden’s entry into the war was unlikely and that Hitler wished no directives for war with Sweden issued.
Sweden’s reaction to Germany’s defense of Courland was not quite what Hitler claimed. Instead of becoming alarmed, Sweden’s military paid scarcely any attention to the German troops in Courland. In early September the Swedes ordered defenses on the island of Gotland strengthened due to the situation in the Baltic States. Otherwise, they did not display much concern. In fact, at the very time Schörner’s supposedly threatening forces went over to the defense in Courland, the Swedish Defense Staff ordered a decrease in readiness Although Swedish military leaders considered an Allied invasion of Norway or Denmark still possible, the threat from Courland seems to have escaped them. In general, the Swedes believed Germany was so tied down in defensive fighting that by the end of 1943 they considered an invasion of Sweden remote indeed. Actually, the Defense Staff’s naval section expressed more concern about a possible threat to the Åland Islands from the Soviet Union once it captured the Baltic States. The Swedes were probably quite content to have German troops in Courland.
Dönitz’s attitude toward Sweden reveals an interesting mixture of fear and contempt. He probably would have liked nothing better than to see Sweden brought to its knees by Nazi armies, because Sweden’s conquest and occupation would have removed a potential threat to the Baltic. But by mid-1943, when Germany seriously began to consider invading Sweden, it was too late. Dönitz had realized that he could not afford any disruption to U-boat training. If Sweden survived the initial onslaught, Allied air and possibly naval forces would arrive and gain direct access to the Baltic. Dönitz realized all too well what that would mean. As Churchill later wrote, “Without command of the Baltic we could not ask for a Swedish harbour. Without a Swedish harbour we could not have command of the Baltic.” Although Dönitz was more than willing to threaten Sweden, as the navy’s proposal to aim V-1 and A-4 rockets at Stockholm demonstrates, his intention was never to provoke the Swedes but to cow them into maintaining the course they had followed since September 1939.