Chief delegates of South Korea, the United States and Japan have met in Seoul to formulate a unified stance at the upcoming six-party talks.

After the trilateral strategy session, South Korea's chief delegate and Deputy Foreign Minister, Lee Soo-hyuck, said the three countries will urge North Korea to dismantle All nuclear programs, including a suspected uranium-based one. Lee said Pyongyang's offer to "freeze" its nuclear programs would not be acceptable unless it is backed up by a firm commitment to dismantle them.

Lee also said the closed door session also dealt with a three-stage strategy proposed by South Korea and China.

The three-stage formula envisages North Korea agreeing to a complete, irreversible and verifiable dismantling of its nuclear weapons programs In return, the other five nations at the talks would supply security guarantees and economic aid.

Assistant Secretary of State James Kelly is leading the U-S delegation to the six-nation talks while the Japanese delegation is headed by Mitoji Yabunaka, director general of the Asia and Oceania Department of the Foreign Ministry.

Delegates from the three countries will be joined by negotiators from North Korea, China and Russia for three days of talks in the Chinese capital to defuse the nuclear crisis. The first round of talks ended in August without an agreement.