North Korea's chief nuclear negotiator plans a rare visit to the United States next month, a report said Friday, amid renewed efforts to bring the communist nation back to international disarmament talks.

A top UN envoy on a mission to Pyongyang this week was also quoted as saying he was "very satisfied" with the outcome of his trip, the first by an official from the world body since 2004.
China, which hosts six-nation nuclear disarmament talks, is trying to persuade the North to return to the negotiations which it quit last April, a month before launching its second atomic weapons test.
South Korea's Yonhap news agency, quoting a diplomatic source, said the North's chief negotiator Kim Kye-Gwan would visit the United States in March, following a trip to Pyongyang in December by US envoy Stephen Bosworth.
"I believe the schedule for Kim's visit has already been fixed," it quoted the source as saying in a report from Beijing, where Kim has been holding talks with his Chinese counterparts. No date was mentioned.
Lynn Pascoe, the UN under-secretary-general for political affairs, met Kim Yong-Nam, the North's official number two leader, on Thursday and passed on a message from Ban to leader Kim Jong-Il but no details were given.
He was quoted as saying by China's Xinhua state news agency on Friday that he was "very satisfied" with the outcome of his four-day trip, aimed partly at reviving the disarmament talks.
But this week's meetings in Beijing have been hard going, according to media reports, with Pyongyang sticking to its demands that UN sanctions be lifted before it rejoins the nuclear dialogue.
The North also wants US agreement to hold talks about a formal peace treaty before it comes back to the forum also grouping South Korea, Japan and Russia.
It was unclear whether Kim's visit would go ahead if the parties fail to agree on restarting the nuclear dialogue.
US State Department spokesman P.J. Crowley, speaking before reports of Kim's trip, said Washington did not rule out further two-way meetings with Pyongyang.
But "we believe firmly that the next meeting that US representatives and others should have with North Korea is through a formal six-party meeting," he said Thursday.
Yonhap said Wu Dawei, China's chief nuclear negotiator who has been meeting Kim, may travel to other six-party member nations after the Lunar New Year this weekend.
"We exchanged important opinions with China on the matters of the peace treaty on the Korean peninsula and the resumption of the six-party talks," Kim told reporters Thursday.
"Results of the meeting will be made known later."
China is North Korea's only major ally, its main trade partner and its chief supplier of desperately needed food and oil. But it was not clear whether it would be able to coax the North back to dialogue.
The two sides were trying Thursday to narrow differences on economic assistance, Yonhap said.
South Korean officials estimate the North will run short of 1.29 million tons of grain this year, equivalent to almost four months' supply.
South Korea Friday proposed more talks with North Korea, despite tensions sparked by the North's artillery drill near the disputed sea border late last month.
The defence ministry said it suggested that working-level military officials meet on February 23 to discuss ways to improve transport and communications links to the Kaesong estate just north of the border.
Some 42,000 North Koreans work at 110 South Korean-funded plants at Kaesong, which was originally developed as a reconciliation project.
Despite political tensions, the two sides have gone ahead with meetings aimed at upgrading or restarting joint business ventures.
Civilian officials met on February 1 to talk about ways to upgrade Kaesong, Those talks ended without agreement after the sanctions-hit North demanded that pay rises for its people should be the priority.