Some communist activists managed to begin a guerrilla movement, headed by the underground Bulgarian Communist Party. A resistance movement called Otechestven front (Fatherland front, Bulgarian: Отечествен фронт) was set up in August 1942 by the Communist Party, the Zveno movement and a number of other parties to oppose the elected government, after a number of Allied victories indicated that the Axis might lose the War. In 1943 Tsar Boris III died suddenly. In the summer of 1944, after having crushed the Nazi defense around Iaşi and Chişinău, the Soviet Army was approaching the Balkans and Bulgaria. On 23 August 1944 Romania quit the Axis Powers, declared war on Germany and allowed Soviet forces to cross its territory to reach Bulgaria. On 26 August 1944 the Fatherland Front made the decision to incite an armed rebellion against the government, which led to the appointment of a new government on 2 September. Support for the government was withheld by the Fatherland Front, since it was composed of pro-Nazi elements, in a desperate attempt to hold on to power. On 5 September 1944 the Soviet Union declared war and invaded Bulgaria. On 8 September 1944 the Bulgarian army joined the Soviet Union in its war against Germany.