Prior to this incident, vessels of the Kriegsmarine customarily picked up survivors of sunk Allied vessels. In September 1942, off the coast of West Africa in the Atlantic Ocean, the German vessels (among them the German U-boats U-156, U-506 and U-507) attempting to rescue survivors of the ocean liner RMS Laconia were indiscriminately attacked by American aircraft, despite having informed the Allies of the rescued Allied soldiers on board (along with many women and children) beforehand.
The order was as follows:
This order, along with War Order No. 154 of 1939, were introduced by the prosecution at the post-war Nuremberg Trial of Grand Admiral Karl Dönitz at which Dönitz was indicted for "war crimes", including the issuance of the "Laconia order":
The prosecution has introduced much evidence surrounding two orders of Dönitz, War Order No. 154, issued in 1939, and the so-called Laconia Order of 1942. The defense argues that these orders and the evidence supporting them do not show such a policy and introduced much evidence to the contrary. The Tribunal is of the opinion that the evidence does not establish with the certainty required that Dönitz deliberately ordered the killing of shipwrecked survivors. The orders were undoubtedly ambiguous and deserve the strongest censure.
The evidence further shows that the rescue provisions were not carried out and that the defendant ordered that they should not be carried out. The argument of the defence is that the security of the submarine is, as the first rule of the sea, paramount to rescue and that the development of aircraft made rescue impossible. This may be so, but the Protocol is explicit. If the commander cannot rescue, then under its terms he cannot sink a merchant vessel and should allow it to pass harmless before his periscope. The orders, then, prove Dönitz is guilty of a violation of the Protocol. (Emphasis added)
In view of all the facts proved and in particular of an order of the British Admiralty announced on 8 May 1940, according to which all vessels should be sunk at sight in the Skagerrak, and the answers to interrogatories by Admiral Chester Nimitz stating unrestricted submarine warfare was carried on in the Pacific Ocean by the United States from the first day of the Pacific War, the sentence of Dönitz is not assessed on the ground of his breaches of the international law of submarine warfare.