SEOUL, South Korea — North Korea put its armed forces on standby today and threatened retaliation against anyone seeking to stop it from firing what regional powers fear will be a missile in the latest barrage of threats from the communist regime.

Pyongyang also cut off a military hot line with the South, causing a complete shutdown of their border and stranding hundreds of South Koreans working in an industrial zone in the North Korean border city of Kaesong.

Today's warning came as U.S. and South Korean troops kicked off annual war games across the South, exercises the North has condemned as preparation for an invasion. Pyongyang last week threatened South Korean passenger planes flying near its airspace during the drills.

Analysts say the regime is trying to grab President Barack Obama's attention as his administration formulates its North Korea policy.

The North also indicated it was pushing ahead with plans to send a communications satellite into space, a provocative launch neighboring governments believe could be a cover for a long-range missile capable of reaching Alaska.

U.S. and Japanese officials have suggested they could shoot down a North Korean missile if necessary, further incensing Pyongyang.

"Shooting our satellite for peaceful purposes will precisely mean a war," the general staff of the North's military said. Any interception will draw a "retaliatory strike operation not only against all the interceptor means involved but against the strongholds" of the U.S., Japan and South Korea.