North Korea must at least take responsive measures to the economic aid it received from the denuclearization dialogue partners in order for the stalled multinational negotiations to restart, a high-ranking official in Seoul said Wednesday.

The senior official at the Foreign Ministry made the comments as North Korea has been showing a renewed willingness to return to the six-nation denuclearization talks, which it walked from at the end of 2008 claiming other partners had failed to keep their side of the promise.

The first round of the aid-for-denuclearization talks, involving the two Koreas, the U.S., Japan, China and Russia, was held in 2003, but not much progress has been made up to date due to Pyongyang’s repeated change of words that led to two atomic tests and several missiles tests.

“Resuming the talks alone doesn’t have much meaning. Making progress through the talks is what matters,” the senior official told reporters on the condition of customary anonymity.

“North Korea should at least show a sincere willingness to play up to the 750,000-ton of heavy oil it received from the international community during the past denuclearization talks,” he said, conditioning the resumption of the talks on the return of the International Atomic Energy Agency inspection team and a moratorium on Pyongyang’s nuclear facilities.

“Even if the talks restart in the future, they will be held in a different format to the past.”

While North Korea’s last-remaining ally China has been responding positively to an early resumption of the six-party talks, South Korea and the U.S. want Pyongyang to first come clean about sinking a South Korean warship earlier this year and better-prove its earnest intent to give up its nuclear ambitions.

Seoul and Washington believe North Korea torpedoed the Cheonan in March, snapping the vessel in half and claiming the lives of 46 young sailors. North Korea denies the accusation while China has remained neutral on Seoul’s findings.

With its ailing leader Kim Jong-il apparently speeding up a power transfer to his youngest son who is still only in his 20s, North Korea is in desperate need to secure outside assistance and avoid further isolation by restarting the talks, pundits say.

North Korea has relied mostly on outside aid to feed its impoverished population of 24 million, often using its nuclear facilities as the main negotiating tool.

South Korea’s “Grand Bargain” proposal is still valid, the Seoul official said, referring to President Lee Myung-bak’s policy to offer the communist North greater rewards, but also attach more stringent conditions to economic aid and engagement.

“The five parties have formed a common understanding (toward the six-party talks),” he said. “China is no exception.”

“It of course has its own issues with North Korea, but is also fully aware of the importance of the ties with us. China also acknowledges the fact that the reunification of the two Koreas should happen through South Korea.”

The two Koreas are technically still at war as their 1950-53 conflict ended in a truce rather than a permanent peace treaty. The U.S. fought on Seoul’s side, while China fought for its Stalinist ally.

By Shin Hae-in (hayney@heraldcorp.com)