In 1940, Hungary Joined the tripartite pact. This made Hungary an axis force. When Germany declared war on the Soviet Union the following year, Hungary would participate in the invasion of Russia any Yugoslavia. However,it was not long before the poorly trained and motivated Hungarians were taking heavy casualties. In 1944, the situation became so bad that Hungary tried to negotiate with the Allies and step out of the war. However, the Germans found out and replaced the Hungarian leader with a pro-war group. After Romania joined the Allies, Romanian and Soviet troops would invade Hungary. Hungary also began loosing control over the captured Yugoslav territory, especially after the Nagykanizsa–Körmend Offensive, which resulted in a major Hungarian defeat. The Allies would capture and almost entirely destroy the entire city of Budapest, the Hungarian Capitol. After the war, Hungary would become part of the USSR.