Following the German assault on the Soviet Union on 22 June 1941, German authorities demanded that Danish communists be arrested. The Danish government complied and directed the police to arrest 339 communists using secret registers. Of these, 246, including the three communist members of the Danish parliament, were imprisoned in the Horserød camp, in violation of the Danish constitution. On 22 August 1941, the Danish parliament passed the Communist Law, outlawing the communist party and communist activities, in another violation of the Danish constitution. In 1943, about half of the imprisoned communists were transferred to Stutthof concentration camp, where 22 of them died.