Soviet control of its non-Russian member republics weakened as movements for democratization and self-government gained strength during the late 1980s, and four republics declared independence in 1990 and 1991. The Soviet coup d'état attempt in August 1991 accelerated the breakup of the USSR, which formally ended on December 26, 1991. The Republics of the Soviet Union become sovereign states—Armenia, Azerbaijan, Byelorussia (later Belarus), Estonia, Georgia, Kazakhstan, Kyrgyzstan, Latvia, Lithuania, Moldova, Russia, Tajikistan, Turkmenistan, Ukraine and Uzbekistan. Historian Robert Daniels says, "A special dimension that the anti-Communist revolutions shared with some of their predecessors was decolonization." Moscow's policy had long been to settle ethnic Russians in the non-Russian republics. After independence, minority rights has been an issue for Russian-speakers in some republics and for non-Russian-speakers in Russia; see Russians in the Baltic states. Meanwhile, the Russian Federation continues to apply political, economic, and military pressure on former Soviet colonies. In 2014 it annexed Ukraine’s Crimean peninsula, the only such action in Europe since the end of the Second World War.