SEOUL, April 2, 2008 (AFP) - The chief US negotiator on North Korea urged the communist state Wednesday to come clean soon about its nuclear programmes, saying he was waiting for a move in the next few days.

Christopher Hill said differences over the North's promised nuclear declaration have narrowed but time is pressing.

'We are very concerned that we really needed this to wrap up by the end of March. Here it is already after the end of March,' Hill told reporters after talks with senior South Korean officials on ways to get negotiations moving.

While some differences on the declaration had narrowed, 'whether they are significant, we won't know until we actually have a declaration.

'So we'll have to see whether we can hear anything new from the DPRK (North Korea) on this, really in the next few days,' Hill said.

Yonhap news agency, quoting a diplomatic source, said Hill was likely to meet his North Korean negotiating counterpart Kim Kye-Gwan in Jakarta on Friday.

The US embassy had no comment but confirmed that Hill, who is Assistant Secretary of State for East Asian and Pacific Affairs, would be in Jakarta on that day to meet Indonesian officials.

A 2007 six-nation denuclearisation deal, involving the United States, China, the two Koreas, Japan and Russia, offers the North energy aid and major diplomatic and security benefits in return for full denuclearisation.

Under the current phase, the North was to disable its main plutonium-producing plants and declare all nuclear activities by the end of 2007.

The North, which tested an atomic weapon in October 2006, says it submitted the declaration last November. But the United States says it has not accounted for a suspected secret uranium enrichment weapons programme or for alleged nuclear proliferation to Syria.

The North denies any secret programme or proliferation moves.

'What is very important about the declaration is to, first of all, have a complete and correct declaration with respect to all the nuclear programmes,' Hill said after meeting Vice-Foreign Minister Kwon Jong-Rak and Deputy Foreign Minister Lee Yong-Joon.

'In particular, we need to know what the plutonium situation is, but also we know the DPRK (North Korea) was engaged in the procurement of things for uranium enrichment. We need to know that status.

'Also, we need to know what is going on with any foreign nuclear cooperation,' said Hill, who also met Unification Minister Kim Ha-Joong.

Hill said his meeting with his North Korean counterpart Kim in Geneva last month had been 'very useful' but failed to break the impasse.

Still, the US envoy said he was satisfied with the pace of disablement despite Pyongyang's recent threat to slow it down.

'I do believe, I continue to believe, the disablement has gone very well, better than many people expected,' Hill said. 'I feel very encouraged by the overall pace and scope of the disablement.

In the final phase, the North would dismantle all its nuclear plants, rather than merely making them unusable, and hand over all nuclear material.

In return, the pact envisages normalised relations with the United States and Japan, an end to sanctions and a peace treaty formally ending the 1950-53 war.