North Korea stepped up disablement of a nuclear reactor it had been threatening to reactivate, U.S. officials said on Friday.
"The North Koreans have, in their efforts, reversed all their reversals in the reactor," State Department spokesman Sean McCormack told reporters, referring to the Yongbyon plutonium reprocessing plant.
The North replaced seals, reinstalled surveillance and restored equipment that had been removed at the reactor, he said.
"In addition to that, they have removed more rods from the reactor," he said. "So, on the reactor, they have actually gone beyond where they were prior to their reversing the disablement."
McCormack, quoting U.S. officials in North Korea, said North Korean specialists removed 60 percent of the fuel rods from the reactor, which can be processed to obtain plutonium for nuclear bombs.
The progress at Yongbyon came after North Korea ended a two-month boycott of a six-nation nuclear disarmament deal following the United States' removal of the country from a terrorism blacklist as an incentive.
McCormack said "there is still work to be done" at reprocessing and fuel fabrication factories. But, he said, he expected nuclear talks among China, Japan, the two Koreas, Russia and the United States will resume "in the coming period of time." He would not discuss specifics because host China has announced the meeting.
On Tuesday, the North allowed U.N. monitors back into the nuclear site. A diplomat in Vienna familiar with the International Atomic Energy Agency's work in the North said the agency's three-member team had resumed monitoring Tuesday.
North Korea stopped disabling Yongbyon in anger over U.S. demands that Pyongyang accept a plan to verify its accounting of nuclear programs as a condition for removal from the terrorism list. The North was threatening to reactivate Yongbyon before the United States agreed to remove it from the list.
Six-nation nuclear talks took on a new tone of urgency after North Korea set off a test nuclear blast in 2006. It then agreed to dismantle its nuclear program in exchange for energy aid and other concessions, though negotiations have since been beset by deadlock and acrimony.