in the face of Truman's attempt to stop Communist expansion, and in 1955 Moscow introduced the Warsaw Pact to counterbalance the Western NATO alliance. Conventional military power showed its continued influence when the Soviet Union used its troops to invade Hungary in 1956 and Czechoslovakia in 1968 to suppress the democratic aspirations of their peoples and keep these countries within the Soviet regime. The Soviet Union and the western forces, led by the US, faced a number of standoffs that threatened to turn into live conflicts, such as the Berlin Blockade of 1948–49 and the Cuban Missile Crisis of 1962, which saw "hawks" on both sides push the respective rivals closer towards war due to policies of brinksmanship. This attitude was tempered by fears of a nuclear conflict and desires among moderates for détente. Under Khrushchev's leadership, Soviet relations with Josip Broz Tito's Yugoslavia were finally repaired with the 1956 dissolution of the Cominform. This decision generated a further rift between the Soviet Union and the People's Republic of China, a neighboring communist state which felt the Soviets were turning their back on the fundamental Marxist–Leninist struggle for the worldwide triumph of communism. This Sino-Soviet split erupted in 1967 when the Red Guard besieged the Soviet embassy in Beijing. Additional conflicts along the Sino-Soviet border followed in 1969. Tension between the political forces in Moscow and Beijing would greatly influence Asian politics during the 1960s and 1970s, and a microcosm of the Sino-Soviet split emerged when the by-then late-Ho Chi Minh's Soviet-aligned Vietnam invaded Pol Pot's pro-Chinese Cambodia in 1978. The Soviets had ensured the loyalty of Vietnam and Laos through an aggressive campaign of political, economic and military aid – the same tactic which allowed the Soviet Union to compete with the United States in a race to establish themselves as neocolonial rulers of newly independent states in Africa and the Middle East. Extensive arms sales made weapons like the AK-47 and the T-55 tank icons of the contemporary wars between Israel and its Arab neighbors. Also significant was the 1968 declaration of the Brezhnev Doctrine which officially asserted the Soviet Union's right to intervene in other nation's internal affairs in order to secure socialism from opposing capitalist forces. This doctrine was used to justify the Soviet invasion of Afghanistan in 1979. In Afghanistan the Soviet forces met a fierce resistance from the Afghans who were supported by the