COPENHAGEN -- An aide to President Lee Myung-bak said Thursday that Seoul may hold working-level talks with Pyongyang to follow up on Lee’s conditional invitation of Kim Jong-il to a global nuclear summit next year.

Pyongyang downplayed Lee’s latest overture in Berlin that he would invite the reclusive North Korean leader to the Nuclear Security Summit in Seoul next spring if Pyongyang made a firm pledge toward denuclearization.

“The North is not aware yet of the details of our proposal,” a Cheong Wa Dae official said in response to reporters’ questions on the North’s apparent refusal.

“The president publicly made the proposal, but we have not officially delivered our position to the North yet. There will be opportunities for us to communicate with the North on this issue.”

A North Korean committee handling inter-Korean relations slammed Lee’s proposal in a statement carried by the North’s official Korean Central News Agency Wednesday, calling it “defiant absurdity.”

The Chosun Sinbo, a Japan-based newspaper that often serves as Pyongyang’s mouthpiece, claimed that North Korea is working hard to achieve denuclearization, but indicated that it was unlikely to accept Lee’s invitation, calling it an “impure attempt.”

The North pledged to abandon its nuclear weapons programs in an aid-for-disarmament deal reached with the U.S., South Korea and other regional powers, but walked out of the talks in 2009.

The North later expressed its interest in returning to the nuclear talks, but its refusal to take responsibility for its two deadly attacks on South Korea has hindered diplomatic efforts to revive the talks that also include China, Russia and Japan.

The newspaper also called on South Korea to review Kim’s proposal for summit talks with Lee, a message delivered by former U.S. President Jimmy Carter after his trip to Pyongyang in late April. Carter, however, was not allowed to meet with either Kim or Lee during his recent trips to Pyongyang and Seoul.

By Kim So-hyun    (sophie@heraldcorp.com)