Following World War II and the USSR-backed pro-Soviet coup d'état in February 1948, Czechoslovakia became part of the Soviet-led Eastern Bloc and was one of the founding members of the Warsaw Pact in May 1955. In August 1968, in response to the Prague Spring pro-democracy reforms of the Czech government, the Soviet-led invasion re-established the hardline Communist rule by force. 108 Czechs and Slovaks died and approximately 500 were wounded as a direct result of the invasion. This damaged relations between the two countries.