SYDNEY, Australia — President Bush's talks with South Korean President Roh Moo-hyun ended on a sour note today not over the war in Iraq, but rather the Korean conflict that ended with a truce more than five decades ago.

As Bush began to wind down his stay at the Asia-Pacific summit, Roh challenged him to make a declaration to end the Korean War. That conflict ended in a truce in 1953, not a peace treaty, so the two sides technically remain at war.

The awkward exchange occurred during the first in a series of sit-downs that Bush had here with leaders from Pacific Rim nations. He also spoke today with Russian President Vladimir Putin and will meet on Saturday with the leaders of Japan, Indonesia and Australia. Protesters plan a march through the city on Saturday, a day after scuffles broke out between riot police and some demonstrators.

Bush's talks with Roh focused on the six-nation negotiations to get North Korea to give up its nuclear ambitions. Soon after the mini diplomatic incident, Christopher Hill, the U.S. envoy handling the talks with Pyongyang, announced that nuclear experts from the U.S., China and Russia will travel to North Korea next week to survey nuclear facilities due to be shut down.

Bush said that during his talks with Roh, he reaffirmed the U.S. position that Washington will consider the war formally over when North Korean leader Kim Jong Il dismantles his nuclear program.

Whatever Roh heard Bush say through his translator, it wasn't good enough.

"I think I did not hear President Bush mention the — a declaration to end the Korean War just now," Roh said.

Bush said he thought he was being clear, but obliged Roh and restated the U.S. position.

"If you could be a little bit clearer in your message," Roh said.

Bush, now looking irritated, replied: "I can't make it any more clear, Mr. President. We look forward to the day when we can end the Korean War. That will end — will happen when Kim verifiably gets rid of his weapons programs and his weapons."

"There was clearly something lost in translation," National Security Council spokesman Gordon Johndroe said in an e-mail to reporters.

Johndroe also said the war was not between the United States and the North but between the North and the United Nations, and Bush alone could not end the war with a simple declaration.