After three years of relative peace, the German-Soviet front returned in 1944 to the land border on the Dniester. On August 20, 1944, a c. 3,400,000-strong Red Army began a major summer offensive codenamed Second Jassy–Kishinev Operation. The Soviet armies overran Bessarabia in a two-pronged offensive within five days. In pocket battles at Chișinău and Sărata the German 6th Army of c. 650,000 men, newly reformed after the Battle of Stalingrad, was obliterated. Simultaneously with the success of the Russian attack, Romania broke the military alliance with the Axis and changed sides. On August 23, 1944, Marshal Ion Antonescu was arrested by King Michael, and later handed over to the Soviets.