The years 1968 and 1969 were racked with war, violence, terrorism, and civil unrest around the world. Wars raged in Vietnam and Nigeria; Soviet and Chinese troops skirmished in a continuing border dispute; Soviet troops entered Czechoslovakia to quell a movement toward liberalization; and El Salvador invaded Honduras. Coups d'etat toppled governments in 'Iraq, Syria, Sierre Leone, Dahomey, the Congo, Mali, the Sudan, Libya, the Netherlands Antilles, Peru, Panama, and Bolivia; states of emergency were declared in Spain, Malaysia, and Chile; violent unrest occurred in West Germany, Spain, Bombay, Pakistan, Argentina, Kenya, and the United States; and student protests erupted in Paris, Mexico City, Czechoslovakia, Argentina, and the United States. United States and Israeli airliners were hijacked, and two Israeli airliners were attacked by terrorists. Moreover, a number of leaders were assassinated, including Somalian president Abdirascid Ali Scermarche; US civil rights leader Martin Luther King, Jr.; US presidential candidate Robert E. Kennedy; US ambassador to Guatemala John Gordon Mein; and Mozambique Liberation Front leader Eduardo Chivambo Mondlane.