U.S. special representative Stephen Bosworth is to visit China, South Korea and Japan on the nuclear stalemate in the Korean Peninsula, the State Department said on Monday.

Bosworth is to travel with senior negotiator Sung Kim, and they will leave Tuesday, spokesman P.J. Crowley said during a regular briefing in Washington.

The visit is part of the six-party disarmament process, the duo are not scheduled to visit the Democratic People's Republic of Korea (DPRK).

Bosworth paid a visit to Pyongyang late last year, but failed to bring the DPRK back to the six-party talks.

In addition to sending envoys to Asia, Secretary of State Hillary Clinton herself is to welcome her South Korean counterpart Yu Myung Hwan on Friday, when Yu visits Washington.

Crowley said Bosworth and Kim would be back in Washington as Clinton and Yu meet.

A diplomatic push is now underway to relaunch the six-party talks. South Korea's Yonhap News Agency reported that chief nuclear negotiator Wi Sung-lac is to visit China on Tuesday. Wi will meet with China's special representative for Korean Peninsula affairs Wu Dawei, discussing current conditions of the region, including the two countries' efforts to resume the stalled six- party talks, and the recent visit by the DPRK's Deputy Foreign Minister Kim Gye-gwan to China.

Kim visited China earlier this month at the invitation of Wu. The two sides exchanged views on China-DPRK relations, the six- party talks and issues of common concern.

The six-party talks, launched in 2003 but stalled last April, involve the DPRK, South Korea, China, Japan, Russia and the United States.