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

The North said the April 5 launch placed an experimental communications satellite into orbit, but US military officials believe it 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'

The North's rocket launch prompted a Security Council condemnation and sanctions [Reuters]
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.

Bosworth was criticised in April when he said he hoped nuclear talks could resume after the rocket launch.

"We will be, as I said earlier, working very closely with our partners to ensure that after the dust of the missiles settles a bit, we get back to the longer-term priority - of the six-party talks," he said on April 3, two days before the rocket took off.

On Monday, North Korea's deputy ambassador to the United Nations dismissed an appeal from the UN secretary general for Pyongyang to return to disarmament talks.

Ban Ki-Moon's call came at the start of a two-week conference on the nuclear Non-Proliferation Treaty, which North Korea withdrew from in 2003.

But Pak Tok-hun, the North's envoy, rejected the appeal.

"We will never return to the six-party talks," he 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."