SEOUL, South Korea —  President Roh Moo-hyun (search) said Saturday that North Korea's nuclear ambitions were the biggest threat to regional peace, and he called for a prompt resumption of six-nation disarmament talks.

The talks aimed at ending the North's nuclear ambitions "must resume soon, and we are making our best efforts for this," Roh said, according to South Korea's Yonhap news agency (search). "The North Korean nuclear issue will definitely be resolved peacefully."

The participants in the talks are the two Koreas, the United States, China, Japan and Russia.

"The North's nuclear issue is the biggest threat now to peace on the Korean peninsula," Roh told war veterans in Seoul, according to the news agency.

Saturday was the 55th anniversary of the start of the Korean War, which ended in 1953 with a cease-fire, not a peace treaty, leaving the two Koreas technically still at war.

The North has boycotted the disarmament negotiations for a year, citing what it calls "hostile" U.S. policies. North Korean leader Kim Jong Il (search) raised hopes last week when he told a visiting South Korean Cabinet minister of a possible return to the table as early as next month, if the North gets appropriate respect from the United States.

The South tried to get the North to commit to that timeframe during Cabinet-level reconciliation talks this week, but failed to get a definite answer.

Efforts to resume the negotiations gained urgency when the North claimed in February it has nuclear weapons. That claim has not been verified, but U.S. intelligence and other estimates say it has as many as six atomic bombs.