In June 1940 the Soviet Union occupied Bessarabia and Northern Bukovina. After General (later Marshal) Ion Antonescu took power in September 1940, Fascist Romania signed the Tripartite Pact with the Axis Powers and subsequently took part in Operation Barbarossa in 1941. An expeditionary force invaded the Soviet Union in Bessarabia and southern Ukraine, alongside the Wehrmacht. The expeditionary force, 'Army Group Antonescu,' was composed on 22 June 1941 of the 3rd Army, the 4th Army, the 2nd Army Corps, and the 11th Infantry Division. The 3rd Army comprised the 4th Army Corps (6th and 7th Infantry Divisions), the Cavalry Corps, the Mountain Corps, two separate artillery battalions, a TA unit, and the Air Force's 3rd Army Cooperation Command. The 4th Army consisted of the 3rd Army Corps, the 5th Army Corps, the 11th Army Corps (two fortress brigades), and the 4th Army Cooperation Command. The army group-level 2nd Army Corps, under Major General Nicolae Macici, controlled the 9th and 10th Infantry Divisions and the 7th Cavalry Brigade. Additionally the 1st Armoured Division was formed for service on the Eastern Front. The Army Group's first offensive, in conjunction with the Eleventh Army, Operation München, enabled Romania to retake the territory immediately east of the Dnister, former part of Moldavia. The Romanian armies saw their first major battles at Odessa and Sevastopol, and in 1942 advanced with other Axis forces deeper into Soviet territory during operation Case Blue. In early November, Romanian mountain troops under the command of Brigadier General Ioan Dumitrache took Nalchik, the farthest point of Axis advance into the Caucasus.