Liaison officers from North Korea and the United States have met regularly at the border village of Panmunjom to discuss the armistice mechanism that effectively ended the 1950-53 Korean War.
But the North's Korea People's Army said it would no longer send its delegates to the border meeting to protest ongoing U.S. military drills and arms build-up around the peninsula, calling them a rehearsal for a U.S. strike on the North.
"It is meaningless to sit together with the U.S. forces side to discuss any issue as long as it remains arrogant," said a KPA message sent to the U.S.-led U.N. Command, which was quoted by Pyongyang's state-run Korean Central News Agency.
The message also warned of "important self-defense measures" if the U.S. military continues pushing the situation on the Korean peninsula "to the brink of war as now in gross breach of the armistice agreement."
North Korea views as a violation of the armistice the U.S. reinforcement of its military presence around the Korean peninsula. An aircraft carrier, stealth fighter jets and an Aegis warship are part of the U.S. presence in the region during the joint war games with South Korea.
Labeled by Washington as part of an "axis of evil" with Iraq and Iran, North Korea has said it would be next target of a U.S. military action after the present war with Iraq. It has criticized Washington for inciting the North's nuclear dispute to create "an excuse for invasion."
The U.S. Forces Korea made no immediate response to the North's statement. U.S. and South Korean military officials said they had informed North Korea about the exercise, which they say is "routine and purely defensive." An earlier U.S. proposal of border talks to discuss the matter was rejected by the North, they said.
Analysts in Seoul said the North's move was aimed at raising the stakes while the United States was distracted by the war in Iraq. On Wednesday, North Korea renewed its call for direct talks with the United States on its nuclear standoff. The United States only wants talks with the North in a multilateral setting.
North Korea has also blamed South Korea for its support of the U.S. stance toward Pyongyang and for the U.S.-led war on Iraq. It has canceled government talks with the South scheduled for this week.
The North's statement came as South Korean Foreign Minister Yoon Young-kwan was flying to Washington for talks Secretary of State Colin Powell to discuss North Korea. During his four-day trip, Yoon was scheduled to meet with Vice President Dick Cheney, Defense Secretary Donald Rumsfeld and national security adviser Condoleezza Rice, officials said.
Yoon also hopes to arrange a summit between President Roh Moo-hyun and President George W. Bush. Officials said Roh would travel to the United States in late April at the earliest.