Updated

The United States is considering a proposal by Seoul to encourage North Korea to freeze its nuclear weapons program, a top South Korean negotiator said Monday ahead of six-nation talks on the issue.

Lee Soo-hyuck (search) did not give details of the proposal, but said it entailed delivering "countermeasures" to North Korea in exchange for stopping and eventually dismantling its nuclear programs.

The development came as diplomats from the United States, South Korea and Japan gathered in Seoul to fine-tune a common position before talks in Beijing aimed at easing tensions over North Korea's nuclear programs.

"The United States shares a significant understanding of the conditions we attached to the proposed North Korean nuclear freeze," Lee said after a morning meeting with U.S. Assistant Secretary of State James Kelly (search) and their counterpart, Japanese Foreign Ministry Director General Mitoji Yabunaka.

"We understand that the United States does not have a strong objection to taking the countermeasures proposed by South Korea as long as the nuclear freeze comes with such conditions."

Maureen Cormack, spokeswoman of the U.S. Embassy in Seoul, said she would have to check on Lee's statement before commenting on the U.S. position.

North Korea had previously proposed freezing its nuclear programs as a first step toward easing tensions. But the impoverished communist nation had demanded energy aid, a lifting of U.S. sanctions and being delisted from Washington's list of terrorism sponsoring nations. The United States had demanded that North Korea first start dismantling its nuclear programs before any concessions are extended.

At the coming talks, Lee said South Korea will push a three-stage plan to resolve the 16-month-old nuclear standoff.

The plan will start with North Korea declaring its willingness to give up its nuclear programs and Washington and its allies expressing readiness to provide a security guarantee.

The second stage will start with North Korea freezing its nuclear programs and then dismantling them in a verifiable way; the other countries would offer corresponding measures.

"The third stage is more of a comprehensive proposal in which resolution of other issues following the dismantlement are discussed," Lee said.

Japan's Kyodo news agency, citing Japanese government officials, said South Korea had proposed extending energy aid in return for a freeze linked to eventual dismantlement.

In Beijing, meanwhile, the top Chinese negotiator Wang Yi told Japanese Vice-Foreign Minister Ichiro Aisawa that North Korea has expressed readiness for complete dismantlement, Japanese media reported Monday.

As its first step, Pyongyang (search) said it would freeze all its nuclear activities, according to Kyodo news agency and public broadcaster NHK.

The nuclear crisis flared in late 2002 when U.S. officials said North Korea acknowledged privately to U.S. representatives that it had the program in violation of a 1994 agreement. It also has a plutonium-based one.

North Korea later denied having a uranium program, and on Saturday called the accusations a "whopping lie."

The United States, South Korea and Japan insist that any solution to the nuclear dispute address the uranium program.