At the end of the war, Soviet troops remained in Iran and established two puppet states in north-western Iran, namely the People's Government of Azerbaijan and the Republic of Mahabad. This led to the Iran crisis of 1946, one of the first confrontations of the Cold War, which ended after oil concessions were promised to the USSR and Soviet forces withdrew from Iran proper in May 1946. The two puppet states were soon overthrown and the oil concessions were later revoked.