The North's declaration was followed shortly after by the demolition of a cooling tower at its Yongbyon nuclear plant – a symbolic gesture intended to show Pyongyang's commitment to the denuclearisation process.

But as Thursday's talks resume in Beijing, envoys from South Korea, China, Russia, Japan and the US will be pressing the North to provide still more details on all of its nuclear activities.

According to the chief US envoy to the talks, negotiators will be seeking to set up a system for what could be a months-long effort to verify the North's declaration of its atomic materials.

Fleshing out details

"Verification itself ... will take several weeks or even months, actually, but we need to agree on how verification will work," Christopher Hill told reporters on Wednesday.

Some basic agreements on the process include interviews with North Korean officials and site visits, Hill said.

North Korea destroyed a cooling tower at its Yongbyon nuclear complex last month [AFP]
"There are a lot of details that need to be fleshed out."

The nuclear standoff began in late 2002 when the US accused the North of seeking to secretly enrich uranium in violation of a 1994 disarmament deal.

The architect of Pakistan's nuclear programme, Abdul Qadeer Khan, said last week that he recalled uranium enrichment equipment being sent from Pakistan to North Korea in 2000.

The US had previously insisted that North Korea detail its alleged uranium enrichment programme as well as nuclear co-operation with Syria in the declaration.

But Washington has apparently backed down from that demand, drawing criticism from American conservatives who say the Bush administration is going too far to strike a deal with the North before leaving office next year.

North Korea's nuclear declaration, which was delivered six months later than the country promised, is said to only give the overall figure for how much plutonium was produced at its main Yongbyon nuclear complex - but no details of bombs that may have been made, and no word on uranium.