SEOUL, South Korea (AP) - South Korea and the United States expressed solidarity Thursday over the deadly sinking of a South Korean warship they blame on North Korea, with high-ranking diplomats calling it a "defining moment" for the US-South alliance.
Tension is high on the Korean peninsula with North Korea warning any moves to punish it at the United Nations would mean armed conflict, possibly nuclear war.
South Korea and the U.S. have urged Pyongyang to avoid fresh provocations and vowed to hold the regime accountable for the March sinking that killed 46 South Korean sailors. North Korea vehemently denies any role.
Senior diplomats from the U.S. and South Korea met Thursday in Seoul and expressed their will to keep their alliance strong.
"We are determined to show that our alliance is standing very firmly together during an absolutely critical period," U.S. Assistant Secretary of State for East Asian and Pacific Affairs Kurt Campbell said in opening remarks at a meeting with South Korean Foreign Minister Yu Myung-hwan.
Yu replied South Korea is "satisfied with the watertight coordination at various levels."
Ahead of another meeting later, Campbell and South Korean Vice Foreign Minister Chun Yung-woo both called the current situation a "defining moment" for the U.S.-South Korean alliance.
"We will demonstrate to the world how well our alliance works," Chun said.
Backed by the U.S. and other allies, South Korea has taken punitive measures against North Korea, including trade restrictions, after blaming it for torpedoing the warship Cheonan near their disputed sea border on March 26. The North reacted angrily, declaring it was cutting off ties with Seoul and threatening to attack.
South Korea has taken the issue to the U.N. Security Council, where both sides stated their case Monday over Seoul's request to punish Pyongyang over the sinking.
On Wednesday, North Korea urged the body to impartially handle the sinking, warning ongoing tension over the sinking could trigger nuclear war.
North Korea has threatened to use its atomic arsenal in previous tense moments with the outside world. While the country is believed to have enough weaponized plutonium for at least a half-dozen nuclear weapons, experts doubt it has the means to use a nuclear weapon in battle.
The threat came hours after the country's U.N. ambassador told reporters at a rare news conference Tuesday in New York that its military will respond if the Security Council questions or condemns the country over the sinking. Sin Son Ho, the envoy, repeated his regime's position that it had nothing to do with the sinking.
The Security Council said in a statement after the Monday presentations it is concerned the sinking could endanger peace on the peninsula, and it urged Seoul and Pyongyang to refrain from any provocative acts.
The two Koreas are still technically at war because their 1950-53 Korean War ended with an armistice, not a peace treaty. The sinking occurred near the disputed western sea border - a scene of three bloody maritime battles.
Separately, a small group of local peace activists protested outside South Korea's Foreign Ministry, where the meetings with Campbell were held. Some South Korean activists and civic groups have questioned the results of a joint investigation South Korea carried out with the U.S. and other countries that concluded Pyongyang was responsible for the sinking.
"If we apply sanctions on North Korea, peace on the Korean peninsula will be destroyed," said protester Yu Young-jae. "So we came here to insist they (Campbell and South Korean officials) stop discussing sanctions on North Korea."