Speaking at the start of a final day of meetings, Hill said it was time for North Korea to "get serious about the issue that made them such a problem…their nuclear activities."
 
He warned that Pyongyang would find itself further isolated if it did not disarm.
 
Credibility
 

"North Korea's claims and its position on financial issues are very firm and inflexibile and that is the biggest cause of the difficulty"

Kenichiro Sasae,
Japanese envoy to talks

Hill's comments came as Japan's envoy to the talks said delegates would consider dropping the current six-nation format, bringing together the two Koreas, Japan, Russia, China and the US.
 
Kenichiro Sasae said a final meeting planned for Friday afternoon would discuss "whether or not to hold the next round."
 
With no progress after three years of talks he said there would be "opinions questioning the credibility of the six-party talks."
 
He did not say what alternative formats would be proposed, if any.
 
Delegates say North Korea has complained about the US blacklisting a Macau bank which Washington says abetted North Korea's alleged illegal financial activities, including counterfeiting of US banknotes and money laundering.
 
Kept apart
 
Japan's envoy says the future of six-nation
talks is in  doubt [GALLO/ GETTY]
In Washington, Condoleezza Rice, the US secretary of state, said that talks on finances and nuclear weapons should be kept apart.
 
In an interview with the Associated Press she said that the North had itself requested a separate working group to discuss the financial curbs.
 
Financial teams from the US and North Korea held two days of talks on the issue separate to the nuclear discussions, but apparently without making any progress.
 
Kenichiro Sasae, the Japanese envoy, said North Korea's envoy at the nuclear talks had repeatedly diverted discussions toward the financial restrictions.
 
"North Korea's claims and its position on financial issues are very firm and inflexibile and that is the biggest cause of the difficulty," said Kenichiro Sasae, Japan's chief negotiator in the six-party talks.
 
North Korea and the other five countries involved in the talks signed an agreement in September 2005 under which Pyongyang agreed to disarm in return for aid and security guarantees.
 
However, the North boycotted negotiations shortly afterwards when the US imposed its financial sanctions.
 
North Korea conducted its first test of a nuclear weapon on October 9 this year.