North Korea (searchon Tuesday accused South Korean navy ships of violating their disputed western sea border repeatedly in recent days, and hours later a South Korean navy speedboat fired warning shots at a Northern fishing boat.

South Korea (searchsaid the fishing boat sailed about 200 yards into its waters and the South's navy fired eight machine-gun rounds. There were no reports of injuries.

The Southern navy boat was about 300 yards from the fishing boat and no hostile actions were taken by North Korean navy ships in the area, said Kim Sung-ok (search), a spokesman at the South Korean military's Office of Joint Chiefs of Staff.

The North Korean fishing boat turned back in five minutes, Kim said.

South Korea's navy ships had also fired warning shots Sunday when eight North Korean fishing boats allegedly entered the South's territorial waters.

Tension along the maritime border comes as the United States is mustering international pressure on the North to abandon its suspected development of nuclear weapons.

"Now that there is an increasing danger of a nuclear war on the Korean peninsula, any military clash between the North and the South may lead to a war," a spokesman for the North Korean Navy Command told Pyongyang's official news agency KCNA.

The unidentified spokesman accused South Korea of deploying warships closer to the border off the peninsula's west coast and infiltrating warships into the North's territorial waters "every day, escalating the tensions."

South Korea is "staging a prelude" to a sea skirmish to "provide the U.S. imperialist warhawks, who are blustering that North Korea is next to Iraq, obsessed with war hysteria, with favorable conditions for a war," he said.

South Korea denies such accusations.

President Bush held separate summits with South Korean President Roh Moo-hyun and Japanese Prime Minister Junichiro Koizumi in May and vowed to take "tougher measures" against North Korea if it escalates tension.

On Monday, Group of Eight world leaders meeting in France accused North Korea of undermining non-proliferation agreements.

North Korea has never recognized a western sea boundary demarcated by the United Nations after the end of the 1950-53 Korean War. It claims a boundary farther south.

This year, the North has conducted missile tests and intercepted a U.S. surveillance plane, maneuvers that were viewed as attempts to pressure the United States into negotiations.

U.S. officials say that at talks in Beijing in April, North Korea claimed that it had nuclear weapons but was willing to scrap its nuclear programs in return for security guarantees and economic aid.

Bush says he prefers a diplomatic end to the standoff, but has not ruled out a military option.