Bosworth, who has been on his Asia tour since Tuesday, was seeking to restart stalled negotiations aimed to end the isolated country´s nuclear ambitions.  

The U.S. State Department said he had no plans as of yet to meet North Korean officials.

In Tokyo, Bosworth met foreign minister Katsuya Okada at his ministry office and also spoke with his Japanese counterpart Akitaka Saiki.

Earlier, Bosworth told reporters in Beijing that North Korea´s neighbours and the United States want fresh momentum in trying to restart the talks.

He also said the halted dialogues would eventually resume after he met South Korea´s chief nuclear envoy Wi Sung-lak in Seoul on Thursday.

U.S. nuclear envoy Stephen Bosworth said that he is convinced six-party talks will eventually resume.

Bosworth met South Korea´s chief nuclear envoy Wi Sung-lak and Unification Minister Hyun In-taek to discuss North Korea´s nuclear weapon programme.

North Korea quit the six-party disarmament talks -- also including South Korea, China, the United States, Japan and Russia -- a year ago.

In May 2009, North Korea then staged its second-ever nuclear test in May 2009, drawing international condemnation and a fresh round of U.N. sanctions.

The North has said it could end its nuclear arms programme if the United States drops what Pyongyang calls a "hostile policy", and it has also demanded that Washington agree to peace treaty talks and lift sanctions.

Washington has said North Korea´s demands for aid and improved relations can be addressed only along with renewed nuclear disarmament steps by Pyongyang.

North and South Korea are still technically at war since the 1950-53 Korean War ended in a truce without a peace treaty.