What is the 1st armed conflict during the Cold War?

Eastern Bloc countries such as Romania and Yugoslavia openly rebelled against the USSR’s such claim.

For the Soviet Union, its leadership role inside the global communist movement was severely damaged by its brutal crackdown of the 1968 Prague Spring in Czechoslovakia and the subsequent enunciation of the Brezhnev Doctrine that said Eastern Bloc countries under the Soviet-led Warsaw Pact had only limited sovereignty, since Moscow had the right to invade to serve the larger purpose of protecting the world communist movement. For China, it was Mao’s bloody ongoing Cultural Revolution aimed at eradicating “China’s Khrushchevs” inside the Chinese Communist Party, and cleansing itself of Soviet “Revisionism,” a CCP attack-phrase meaning Moscow’s apostasy from orthodox Marxism–Leninism. At the time, both China and the Soviet Union were largely discredited by their own political madness.

The background for the crisis of 1969 between Beijing and Moscow is multifaceted and complicated. In 1969, China and the Soviet Union, the two largest communist states, were engaged in a series of ferocious military conflicts that nearly brought them to a general and nuclear war.

What is the 1st armed conflict during the Cold War?