The secret protocol contained in the 1939 Molotov–Ribbentrop Pact between Germany and the Soviet Union had relegated Estonia, Latvia, and Lithuania to the Soviet sphere of influence. In late 1939 and early 1940, the Soviet Union issued a series of ultimatums to the Baltic governments that eventually led to the illegal annexation of the states. (At about the same time, the Soviet Union was exerting similar pressure on Finland.) About 30,000 Soviet troops entered the Baltic states during June 1940, followed by arrests of their leaders and citizens.