"The purpose of the trip is to work with our allies to find a way forward and convince the North to come back to the negotiating table," Robert Wood, spokesman for the US state department, told reporters earlier this week.

North Korea announced last month that it was pulling out of the six-nation talks process following the UN Security Council's condemnation of its rocket launch in early April.

The North's rocket launch prompted a Security Council condemnation and sanctions [Reuters]
It says the April 5 launch placed an experimental communications satellite into orbit, but US military officials believe the launch was cover for a test of a long-range missile.

Following the UN condemnation, Pyongyang announced it was pulling out of the denuclearisation talks, which it described as "useless", and said it would never return.

It also expelled international nuclear inspectors and declared that it would restart all its nuclear facilities.

Analysts have said the North may be pushing for direct bilateral talks with the US, although the Obama administration has said all negotiations on the North's nuclear programme must involve its neighbours via the six-nation framework.

The talks, hosted by China, have brought together envoys from the US, Russia, China, Japan and the two Koreas.

'New war'

Bosworth's visit to Asia also comes as North Korea keeps up a stream of rhetoric against the US, accusing Washington earlier this week of plotting a nuclear attack against the country.

In an editorial published on Tuesday, the ruling party newspaper Rodon Sinmun said the country faced "a new war scheme by US hostile forces" and vowed the North would never give up its nuclear weapons programme.

The editorial came a day after North Korea's deputy ambassador to the United Nations dismissed an appeal from the UN secretary general for Pyongyang to return to disarmament talks.

"We will never return to the six-party talks," Pak Tok-hun told Reuters news agency.

"As long as they are trying to infringe on our sovereignty, we don't see any need, any necessity to participate in the six-party talks."