U.S. nuclear envoy Christopher Hill says months of deadlock over dismantling North Korea's nuclear program must come to an end.
Speaking with reporters in Singapore, ahead of key negotiations with his North Korean counterpart Kim Kye Kwan, Hill said there must be some progress without any more delays.
Hill and Kim both arrived in Singapore Monday, for a Tuesday meeting that will focus largely on a declaration of all the North's nuclear activities and stockpiles.
Negotiations over North Korea's nuclear program have been stalled since December, when the U.S. said Pyongyang failed to account for uranium enrichment that it has never publicly acknowledged.
South Korean media suggest that North Korea and the U.S. are nearing an agreement on the declaration.
The U.S. State Department has played down speculation of a possible breakthrough during the Singapore talks.
Five years ago, the six-party talks began in an effort to get Pyongyang to end its nuclear weapons program in exchange for diplomatic benefits and energy aid. The other participants are China, Japan, Russia and South Korea.
Also Friday, North Korean state media announced that the country is replacing its long-serving ambassador to the United Nations, Pak Gil Yon. A Korean Central News Agency report said the new ambassador, Sin Son Ho, was appointed by a parliamentary decree.
North Korea does not have diplomatic relations with the United States, but it often communicates with American officials through its U.N. mission.
Some information for this report was provided by AFP and AP.