North Korea's top negotiator to the six-way talks Kim Kye-kwan says his country can return to the multilateral dialogue any time, as it has taken all defensive measures through its October nuclear test.

Kim arrived in Beijing Tuesday morning, saying his visit was at the “kind” invitation of U.S. counterpart Christopher Hill.

The North Korean official appeared ready to negotiate, saying he wants to narrow gaps with the U.S. He noted, however, that many thorny issues remain.

Kim is scheduled to see Hill on Tuesday, with Chinese Vice Foreign Minister Wu Dawei playing a mediating role. Hill is expected to convey the U.S. stance to his North Korean counterpart at the meeting.

The U.S. is known to be demanding that the North reveal its entire nuclear program and freeze its nuclear facilities in return for energy aid, as stipulated in last year’s September 19th Joint Statement.

According to diplomatic sources in China, South Korea's chief negotiator Chun Yung-woo discussed with U.S. nuclear envoy Hill what measures North Korea should implement to revive the stalled six-party talks and the rewards it can expect for implementing them.