US nuclear envoy Christopher Hill is to leave for Beijing and Moscow next week as talks intensify seeking a nuclear declaration from North Korea, the State Department said Friday.

State Department deputy spokesman Tom Casey also told reporters that Hill, who leaves Washington on Monday for Beijing, was open to meeting with North Korea's top nuclear negotiator Kim Kye-Gwan.

"The usual rules apply (for such a meeting). Nothing scheduled, but the North Koreans know he's traveling and if they see an interest or desire to do so, they'll arrange something," Casey said.

Hill will be in Beijing from May 27 to May 29, then Moscow from May 29 to May 31 before heading to Sweden for the Stockholm-China Forum, hosted by the German Marshall Fund, and then returning to the United States on June 2, Casey said.

The US envoy will meet with his Chinese and Russian counterparts in the six-party negotiations after meeting his South Korean and Japanese counterparts in Washington on Monday.

Hill said this week that the pace of talks for North Korea's nuclear disarmament is quickening as he admitted hopes were rising that Pyongyang will finally hand over its declaration on its nuclear programs.

The North, which staged a nuclear test in October 2006, is disabling its plutonium-producing reactor and other plants under a six-party deal reached last year with the United States, China, Japan, Russia and South Korea.

But disputes over the declaration due December 31 have blocked the start of the final phase of the process -- the permanent dismantling of the plants and the handover of all material.

In return for total denuclearization, the North would receive energy aid, a lifting of US sanctions, the establishment of diplomatic relations with Washington and a formal peace treaty.

North Korea also missed an end-of-year deadline to completely disable its nuclear plants.

North Korea raised hopes it would hand over the declaration after giving the United States earlier this month 18,000 documents of operating and production records for the five-megawatt reactor and reprocessing plant in Yongbyon.

US officials say the documents will help verify the declaration when it is eventually submitted.

In addition to the declared plutonium operation, Washington said the declaration must clear up suspicions about an alleged secret uranium enrichment program and suspected involvement in building a nuclear reactor in Syria on a site that Israel bombed last September.

The North denies both activities. Under a reported deal, it will merely "acknowledge" US concerns about the two issues in a confidential separate document to Washington.