On the outside too, the PMR, leading a country that had joined the Warsaw Pact, remained an agent of political repression: it fully supported Khurshchev's invasion of Hungary in response to the Revolution of 1956, after which Imre Nagy and other dissident Hungarian leaders were imprisoned on Romanian soil. The Hungarian rebellion also sparked student protests in such places as Bucharest, Timișoara, Oradea, Cluj and Iași, which contributed to unease inside the PMR and resulted in a wave of arrests. While refusing to allow dissemination of Soviet literature exposing Stalinism (writers such as Ilya Ehrenburg and Aleksandr Solzhenitsyn), Romanian leaders took active part in the campaign against Boris Pasternak.