US officials met twice last week with North Korean officials in New York to tell them the US was ready to resume nuclear negotiations and wanted to resolve the issue diplomatically, State Department spokesman Adam Ereli said.
"We told the North Koreans that the six-party process is the venue for resolving the nuclear issue and we called on North Korea to follow through on its commitment to the six-party talks," Ereli said Monday.
He said the US requested the meetings because it was felt a face-to-face presentation of the US position might be effective.
Ereli said the US has meetings with North Korea's UN diplomats in New York from time to time when they serve a useful purpose to pass messages and make points known.
He said he did not know how North Korea responded to the US presentation made by Joseph DeTrani, the State Department's special envoy for North Korea negotiations
Ereli said DeTrani left Sunday on a trip to China, South Korea and Japan to continue consultations on getting the nuclear negotiations going again. Russia also is involved in the talks.
Three rounds of six-nation talks aimed at persuading the North to halt weapons development have taken place since last year but without a breakthrough. North Korea boycotted a fourth round scheduled for September and analysts believed it was holding out for a change in the White House.
On Saturday North Korea said after the talks in New York it had concluded that Pyongyang should hold off on nuclear negotiations until the US changes its "hostile" policy toward the country.
The report, from Pyongyang's official news agency KCNA, said officials met on Tuesday and Friday.
Mohamed ElBaradei, the head of the International Atomic Energy Agency, told The New York Times he was now certain the nuclear material his agency once monitored in North Korea had been converted into fuel for four to six nuclear bombs.
ElBaradei said his judgment that North Korea had converted its stockpile of spent nuclear fuel into weapons-grade plutonium was not based on new intelligence.
Instead, he said, it was based on the agency's years of accumulated knowledge of North Korea's abilities, and the amount of time that had passed since North Korea ejected inspectors and began removing the 8,000 spent nuclear fuel rods that inspectors had been monitoring.
"I'm sure they have reprocessed it all," he said. "We know they have the fissile material," he said, referring to the rods, which can be reprocessed into weapons-grade plutonium.
"The production process is not that difficult" to turn the rods into bomb fuel, and now enough time has passed for North Korea to have solved any production problems, he said.
North Korea agreed in 1994 to freeze plutonium production but in 2002 renounced the deal and ejected the IAEA after Washington accused it of trying to produce highly enriched uranium.
Asked whether the two New York meetings had moved the ball forward on North Korea, US State Department number-two Richard Armitage said: "I'm not sure."
"We'll have to wait until they digest what was said," said Armitage, who last week expressed the hope that the six party talks could resume by the first week of January.
The State Department refused to discuss the specifics or get into details on the meeting with the North Koreans.
Ereli said the US indicated to them it remained ready to resume the six-party talks at an early date, without preconditions, and called on Pyongyang to follow through on its commitment to continue with the discussions.