The United States on Tuesday expressed "disappointment" over an impasse in global disarmament talks that have set back efforts to limit access to materials that can be used to build a nuclear weapon.

Rose Gottemoeller, US assistant secretary of state for arms control, verification and compliance, alluded to foot-dragging by nuclear-armed Pakistan and warned "our patience will not last for ever."

"I have to tell you that I expressed some disappointment at the fact that the conference on disarmament over the last years has been less energetic in terms of pursuing its overall agenda," she told reporters after the meeting.

"We will do everything so that we can have talks go forward -- there is no reason to stand still," Gottemoeller added.

She spoke after a meeting at the United Nations that failed to make progress toward an agenda for disarmament talks, including a proposed Fissile Material Cutoff Treaty, which would limit access to materials that could be used to make nuclear weapons.

"We will definitely continue to press" for an accord, she said.

"We regard this delay as unwarranted and out of step with the expectations of the wide majority of states seated here today," she said.

Since last year, Pakistan has blocked a resumption of negotiations on the nuclear agenda for the Disarmament Conference, fearing that an agreement would lock in an imbalance in its nuclear arsenal vis-a-vis that of India.

earlier related report
N.Korea restores facilities at nuclear reactor: S.Korea
Seoul (AFP) Oct 5, 2010 - North Korea is restoring facilities at its Yongbyon nuclear reactor, the source of weapons-grade plutonium in the past, South Korea's defence ministry said Tuesday.

"North Korea is restoring nuclear facilities and continuing maintenance activities at Yongbyon," a spokesman quoted Defence Minister Kim Tae-Young as telling parliament on Monday. "It is engaged in new construction and large-scale excavation."

The foreign ministry said the South is closely monitoring the work.

"There are some activities going on but we have no information on what these are for," said spokesman Kim Young-Sun. "The government is watching closely the activities there and exchanging information with other countries."

An unidentified government official was quoted by Dong-A Ilbo newspaper as saying that two rectangular buildings were being built next to the site of a cooling tower demolished in 2008.

A private US research institute reported last week that new construction or excavation was under way at Yongbyon.

The Institute for Science and International Security (ISIS) said tracks made by heavy machinery along with construction or excavation equipment were visible in satellite photos.

ISIS said there appeared to be ongoing construction of two small buildings next to the former tower, which the North blew up in June 2008 in front of foreign media to dramatise its commitment to nuclear disarmament.

The institute said the purpose of the work is unclear but bears watching.

The North's current plutonium stockpile is believed to be enough for six to eight bombs.

North Korean Vice Foreign Minister Pak Kil-Yon told the United Nations last week his country must strengthen its nuclear deterrent in the face of what he called threats from the United States.

The North shut down Yongbyon in July 2007 under a six-nation aid-for-disarmament accord. The following summer it destroyed the tower.

But six-party talks became bogged down in December 2008 over ways to verify the North's denuclearisation. In April 2009 Pyongyang abandoned the talks and said it had resumed reprocessing spent fuel rods to make plutonium.

In May 2009 it conducted an atomic weapons test, its second.

The North has indicated willingness in principle to return to the six-party forum chaired by its ally China. But it says it wants separate talks with the United States about signing a permanent peace treaty on the peninsula.

South Korea and the United States, which accuse the North of a deadly March attack on a South Korean warship, have responded warily. Japan and Russia are also members of the forum.