After the Molotov–Ribbentrop Pact and the Soviet invasion of Poland in 1939, Vilnius and its surroundings of up to 30 kilometres were given to Lithuania in accordance with the Soviet–Lithuanian Mutual Assistance Treaty of October 10, 1939, and Vilnius again became the capital of Lithuania. However, in 1940, Lithuania was annexed by the Soviet Union, forcing the country to become the Lithuanian SSR. Since the restoration of Lithuanian independence in 1991, the city's status as Lithuania's capital has been internationally recognized.