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 London bus attack 1978 London bus attack On 20 August 1978, a staff bus of El Al airlines in London was attacked by Palestinian terrorists. A flight attendant and one terrorist were killed in the attack, and nine people were wounded. At around 13:30, a minibus with staff of the El Al airlines was attacked during a stopover at the Europa Hotel in Grosvenor Square, Mayfair, central London, when two or three men opened fire with submachine guns and hand grenades. An El Al flight attendant was killed in the attack, while members of a wedding party were among those wounded by gun