North Korea has disclosed producing more arms-grade plutonium for its atomic weapons programme, a day after threatening to "go its own way" unless the US agrees to direct talks on the nuclear standoff, official media has reported.

The Korean Central News Agency (KCNA) said on Tuesday that Pyongyang had "successfully completed reprocessing 8,000 spent fuel rods by the end of August" at its Yongbyon nuclear complex.

"Noticeable successes have been made in turning the extracted plutonium weapon-grade for the purpose of bolstering up the nuclear deterrent," it said.

Experts said the North might be able to produce enough material for one more atomic weapon from the fuel rods, adding that the North already has enough fissile material for about six to eight nuclear weapons.

Direct talks

The announcement came amid North Korean attempts to pressure the US into accepting its demand for direct talks.

Washington said it is willing to meet one-on-one with the North if it leads to the resumption of six-party talks involving China, Japan, the two Koreas, Russia and the US, but it has not made any decision on whether to hold direct talks.

North Korea restarted its nuclear facilities at its Yongbyon complex in April in anger over a UN rebuke of its rocket launch, which was denounced as a test of its long-range missile technology.

KCNA said the UN censure of what it called a peaceful satellite launch "was a grave insult to the dignity of its people".

It said it was compelled to bolster "its deterrent for self-defence to cope with the increasing nuclear threat and military provocations of the hostile forces".