Koreas resume talks after 10-month hiatus

The South also promised the North "a substantial proposal" if it returns to six-party talks.

The first direct talks between the rival Koreas in 10 months came even as a top US security official promised unspecified action against North Korea if it carried out a nuclear test.

South Korea said it urged the North to return to six-party nuclear disarmament talks.

A Japanese official on Sunday echoed comments from Stephen Hadley, President Bush's national security adviser, that a North Korean nuclear test would provoke action.

"We've seen some evidence that says that they may be preparing for a nuclear test," Hadley said in an interview with CNN. "Obviously, that would be a serious step, and it would require us to consult very closely with our colleagues on the six-party talks for what kind of response we should make."

He said a nuclear test "would be something where the North Koreans would be defying not only us, but our partners in the six-party talks, and action would ... have to be taken."

Shinzo Abe, secretary-general of Japan's ruling Liberal Democratic Party, said Tokyo would take the issue to the United Nations.

"It is unthinkable not to impose any sanctions in case of a nuclear testing," Abe said.

Last week, North Korea ratcheted up the issue by claiming it had completed removing spent fuel rods from a reactor at its main nuclear complex and said it would strengthen its nuclear arsenal. That raised concerns about a possible nuclear test, spurring the public warnings by US and Japanese officials.