The New York Times reports that President Roh Moo-hyun pressed U.S. President George W. Bush in a post-summit news briefing Friday to formally end hostilities toward North Korea.

The daily said it's not the first time the two leaders have clashed over North Korea policy.

When the South Korean president confirmed Bush's mention of a peace treaty to end the Korean War, Bush said that it was up to the North Korean leader and that Pyongyang must remove its nuclear weapons in a verifiable manner.

When Mr. Roh further pressed the U.S. president to be clearer, Bush cut him off, saying that he couldn't "make it any more clear."

Despite the apparently testy exchange, the Times quoted White House spokeswoman Dana Perino as describing the meeting as "very warm."

U.S. officials chalked up the exchange to a translation problem, dismissing any speculation of tension between the two leaders who were meeting in Sydney on the sidelines of an Asia-Pacific regional forum.