What june 1950 action caused the united nations to respond with military action

The reason why united nations responded with military action because of the war between the north and the south Korea, North Korea was a communist area because it was dominated by Russia at that time. The Russian presence had complicated matters as the Russians would not allow United nations observers in. The invasion of north Korea took place on June 25, 1950, where the security council of the United Nations met the same day. at the meeting, America claimed that North Korea had broken the world peace and called the united nations to use force to get the north koreans out as they hade ignored the security resolution of the June 25th.