German forces started Operation Aster to evacuate its 50,000 soldiers and 20,000 civilians through Tallinn and Paldiski. On the way, the hospital ship "Moero" was attacked and sunk by the Soviet Air Force, killing 637 of its passengers. The retreating German forces avoided conflict with the Red Army in Tallinn and the invading army saw only little resistance by Estonian units led by Rear Admiral Johan Pitka. The Red Army entered Tallinn on 22 September and Paldiski on 24 September 1944.