North Korea is warning of new clashes at sea, accusing South Korean naval vessels of violating their disputed maritime border. The charge comes just days after the two Koreas agreed on measures to prevent maritime disputes.

Communist North Korea says the South is engaging in reckless actions by deploying naval ships, patrol boats and helicopters along their common but disputed border in the Yellow Sea.

The official Korean Central News Agency in Pyongyang Wednesday quotes the North Korean military command as saying if Seoul continues such acts, it will be forced to deliver what it called "merciless blows." The report accuses South Korea of deploying the vessels as a pretext to tighten control over fishing boats and inspections.

It adds that the security and firing exercises of the South Korean Navy are "seriously getting on the nerves" of North Korean seamen.

The two Koreas, in what was heralded as a significant breakthrough, last week agreed on measures to reduce border tensions. Those pledges include sharing radio frequencies and other forms of communication to reduce the chances of confrontation.

Naval boats from both sides engaged in deadly clashes in 1999 and 2002 during the fishing season.

Regional analyst Robert Broadfoot, the head of Political and Economic Risk Consultancy in Hong Kong, says North Korea's latest rhetoric is nothing surprising.

"Talks are something that have been on and off for years and years," he said. "It's like spinning wheels. So to make any conclusions because North Korea makes some accusations after a set of talks, no one's going to lose any sleep over that."

Last Friday, Seoul said two North Korean patrol boats briefly crossed the disputed Yellow Sea border, just hours after the inter-Korean agreement.

The two Koreas technically remain at war since their 1953 armistice. The North does not recognize the de facto sea border - drawn up by the U.S.-led United Nations forces at the end of the Korean War. Pyongyang wants the sea frontier redrawn farther south.

The latest inter-Korea exchange comes as the United States has proposed cutting its troops presence in South Korea from 37,000 to just under 25,000.

South Korea is reportedly not happy with the timetable for the reductions. But the U.S. State Department says Washington is not reducing its defense commitment to Seoul.