The occupation of the Baltic states was the military occupation of the three Baltic states—Estonia, Latvia and Lithuania—by the Soviet Union under the auspices of the Molotov–Ribbentrop Pact on 14 June 1940 followed by their incorporation into the USSR as constituent republics, unrecognised by most Western powers. On 22 June 1941 Nazi Germany attacked the USSR and within weeks occupied the Baltic territories. In July 1941, the Baltic territory was incorporated into the Reichskommissariat Ostland of the Third Reich. As a result of the Baltic Offensive of 1944, the Soviet Union recaptured most of the Baltic states and trapped the remaining German forces in the Courland pocket until their formal surrender in May 1945. The Soviet "annexation occupation" (Annexionsbesetzung or occupation sui generis) of the Baltic states lasted until August 1991, when the Baltic states regained independence.
The Baltic states, the United States and its courts of law, the European Parliament, the European Court of Human Rights and the United Nations Human Rights Council have all stated that these three countries were invaded, occupied and illegally incorporated into the Soviet Union under provisions of the 1939 Molotov–Ribbentrop Pact, first by the Soviet Union, then by Nazi Germany from 1941 to 1944, and again by the Soviet Union from 1944 to 1991. This policy of non-recognition has given rise to the principle of legal continuity, which holds that de jure, or as a matter of law, the Baltic states had remained independent states under illegal occupation throughout the period from 1940 to 1991.