Original sentence: The Occupation of Baltic states generally refers to the occupation of the Baltic states (Estonia, Latvia, and Lithuania) first by the Soviet Union, then Nazi Germany, and again by the Soviets during World War II, and to the Soviet presence in the Baltics from 1945 until the re-establishment of their independence
Edited sentence: The Baltic NATO and EU allies and Australia, Switzerland maintain that Baltic States were occupied by the Soviet Union in June 1940,  The Occupation of Baltic states generally refers to the occupation of the Baltic states (Estonia, Latvia, and Lithuania) first by the Soviet Union, then Nazi Germany, and again by the Soviets during World War II, and to the Soviet presence in the Baltics from 1945 until the re-establishment of their independence