SEOUL, South Korea - North Korea appeared increasingly unlikely to meet a weekend deadline to shut down its nuclear reactor, staying silent Thursday about whether it was satisfied with a US solution to a financial dispute that has stalled the disarmament process.

US Assistant Secretary of State Christopher Hill talks to the media after a luncheon meeting with his South Korean counterpart Chun Young-woo in Seoul Thursday, April 12, 2007. [AP]

The US, South Korea and China said the North has not withdrawn some $25 million that was unfrozen this week in a bank in the Chinese territory of Macau. Washington had blacklisted the Banco Delta Asia in September 2005 for allegedly helping the North launder money and pass counterfeit $100 bills.

North Korea cited the dispute in refusing to abandon its nuclear program.

"We have truly fulfilled our role in this and now it's up to" North Korea, US Assistant Secretary of State Christopher Hill said in Seoul.

US officials and experts say the process of shutting down a reactor and having UN nuclear inspectors verify it would probably take several days - making it likely that Saturday's deadline would mark the latest failure in a nuclear standoff that has lasted more than four years.

The problem in reaching the first of many milestones along the road to the North's possible disarmament raises questions about how smoothly the process will go forward. It was unlikely that the US or other countries would take any punitive action, however, as Washington also failed to resolve the bank issue within 30 days as promised.

The International Atomic Energy Agency was still awaiting an invitation from North Korea for a preliminary visit, a diplomat familiar with the issue said on condition of anonymity because he was not authorized to speak to the media.

After a visit by two senior IAEA officials, the agency's board would convene to approve the first return of inspectors since December 2002, when North Korea kicked them out and quit the Nuclear Nonproliferation Treaty. Weeks could elapse between an invitation from the North and the board meeting, the diplomat said.

New negotiations over the North's nuclear program began in 2003, but the six-nation disarmament talks failed to yield any tangible progress in getting the government to abandon weapons development.

The North produced enough plutonium to make as much as a dozen bombs and conducted its first nuclear test in October. But after international pressure and a US pledge to resolve the financial issue, the North agreed in February that it would shut down its sole operating nuclear reactor by Saturday in exchange for an initial shipment of energy. It is to receive a total of 1 million tons of heavy fuel oil for dismantling its nuclear weapons programs.

Even China, the host of the six-nation talks, acknowledged the difficulties in the process, which also include Japan, Russia and South Korea.

"The six-party talks have never been smooth sailing but as long as we have a common willingness and resolve we can overcome all difficulties and push forward this process," Chinese Foreign Ministry spokesman Qin Gang said.

Although time was running short before the Saturday deadline, Hill maintained it was "possible to get going on this process in the next two days."

"This is about (North Korea's) willingness with respect to denuclearization," he said.

South Korean nuclear envoy Chun Young-woo called for patience and said other countries should wait "another few days" until North Korea responds, noting it typically does not act quickly.

The agreement doesn't specify how far North Korea has to go to meet the demand for a shutdown, or define the procedure.

Matthew Bunn, a senior research associate in the Belfer Center for Science and International Affairs at Harvard University's John F. Kennedy School of Government, said shutting down and sealing the Yongbyon reactor could be done in hours, or even minutes.

He said monitors should then be present to seal it so that any tampering would be evident to them in future inspections.

"The obvious question is whether or not the inspectors will arrive by this weekend," he said.

Bunn said irreversibly disabling the reactor, which was agreed upon as a future goal, will require more time.

Meanwhile, New Mexico Gov. Bill Richardson met South Korean President Roh Moo-hyun to discuss his four-day mission to North Korea to recover six sets of remains believed to be of American soldiers from the Korean War.

Richardson, a US presidential candidate, said Wednesday in Seoul that North Korea agreed to welcome UN nuclear inspectors within a day of receiving its frozen funds, but wanted to extend the deadline for shutting down its reactor by 30 days - which the US delegation rejected.

A newspaper aligned with Pyongyang wrote Thursday that the handover of the US soldiers' remains was proof that the North was maintaining a policy to "end hostile relations with the US"

The Japan-based Choson Sinbo noted the release of the frozen funds but said the delay in disarmament was caused by an "evasive" US attitude.

"It was because the US did not prepare conditions for the (North) to take a step toward denuclearization that the (North) held off on implementing" its February shutdown pledge, the newspaper wrote.

Hill said he would fly to Beijing on Friday to meet Chinese officials and would also be willing to see chief North Korean nuclear envoy Kim Kye Gwan there.