The top U.S. negotiator on North Korea's nuclear weapons program has arrived in China on a trip that is focused on helping restart stalled disarmament talks.

Speaking with reporters Monday in Beijing, Christopher Hill says he has met with Chinese officials and welcomed any opportunity to meet with North Korea's representatives in China.

Hill says he always lets North Korean officials know when he is town, adding that if they were interested in holding talks, he is ready to meet with them.

During his visit to the region, which includes stops in South Korea Tuesday and Japan later this week, Hill is also making preparations for a trip by U.S. Secretary of State Condoleezza Rice later this month.

North Korea was supposed to disable its main atomic plant by December 31 and list all its nuclear programs, under a deal negotiated by the two Koreas, China, the United States, Russia and Japan. Washington says the list Pyongyang submitted was not complete.

North Korea's number two leader, Kim Young Nam, has blamed the United States for the stalemate.

On Saturday, U.S. nuclear experts just back from North Korea said Pyongyang wants promised energy aid, and removal from a U.S. terrorism and sanctions blacklist before it offers full disclosure of its nuclear program.

The experts said North Korea has slowed the removal of nuclear fuel rods from its Yongbyon reactor, and that it could take months before the reactor is shut down.

Some information for this report was provided by AFP.