Bulgaria–United States relations to work. Bulgaria became a member of the Warsaw Pact on May 14, 1955. Though no Soviet troops were stationed on Bulgarian soil, in 1968, Zhivkov sent a Bulgarian division to join Polish, Hungarian and Soviet troops to crush a popular uprising in Prague. In 1978, the Bulgarian secret police were implicated in the assassination in London of Georgi Markov, a Bulgarian dissident who was a correspondent for the BBC World Service, Deutsche Welle radio and the U.S. sponsored Radio Free Europe. Markov was assassinated with a poisoned umbrella on September 7, Zhivkov's birthday. The rise of democratic movements across
1978 Balkan Bulgarian Tupolev Tu-134 crash or if the aircraft was under control at the moment of impact. 1978 Balkan Bulgarian Tupolev Tu-134 crash The 1978 Balkan Bulgarian Tupolev Tu-134 crash was an accident that occurred on 16 March 1978, when a Balkan Bulgarian Airlines Tupolev Tu-134 airliner on an international flight from Sofia, Bulgaria, to Warsaw Airport, Poland crashed. On departure from Sofia, the aircraft was climbing to , but at it turned on a heading of 050. It turned again to 270 then began an abnormal descent. The aircraft crashed near the village of Gabare, 130 km northeast of Sofia. All 73 on board