VIENNA, Austria — North Korea moved closer to restarting its nuclear arms program Wednesday, barring U.N. inspectors from its main plutonium reprocessing plant and announcing it will reactivate the facility that provided the material for its atomic test blast.
The move fed fears about a resurgent nuclear North Korea, but there also is speculation it might be motivated by negotiating strategy. Pyongyang could use the year needed to restart its sole reprocessing plant to wrest more concessions from the U.S. and others seeking to end the atomic program.
Still, coming amid reports leader Kim Jong Il suffered a stroke, the nuclear reversal is raising nervousness about a breakdown in the international attempt to coax the North out of its confrontational isolation — a point addressed Wednesday by Secretary of State Condoleezza Rice.
U.S. diplomats are talking with other nations involved in bargaining with the North at this week’s meeting of the U.N. General Assembly.
Any move by Pyongyang to restart its nuclear program ‘‘would only deepen its isolation,’’ Rice warned. ‘‘We strongly urge the North to reconsider these steps and come back immediately into compliance with its obligations’’ under a disarmament-for-aid agreement reached in six-nation talks.
Hours earlier, the International Atomic Energy Agency announced that North Korean officials ‘‘informed the IAEA inspectors that they plan to introduce nuclear material to the reprocessing plant in one week’s time.’’
The statement from the Vienna-based U.N. agency said Deputy IAEA Director General Olli Heinonen told the IAEA board that after a request from North Korea, his inspectors removed all agency seals and surveillance equipment from the reprocessing plant and its immediate area.
That work ‘‘was completed today,’’ Heinonen said, according to the statement.
It also said North Korea barred IAEA inspectors from further access to the Yongbyon nuclear complex.
North Korea had signaled in recent days that it would break out of the disarmament deal, announcing it was making ‘‘thorough preparations’’ to restart Yongbyon.
‘‘What they’ve done is trouble,’’ said Gregory L. Schulte, the chief U.S. delegate to the IAEA, and his expression of concern was echoed by the South Korean Foreign Ministry spokesman, Moon Tae-young.
But their comments were measured, reflecting concerns that harsh condemnation could backfire by accelerating the North’s move to restore its nuclear operations.
North Korea’s recent moves have deepened the guessing game about leadership in Pyongyang, where Kim is reportedly ill and possibly incapacitated.
‘‘There is uncertainty about who is in charge, or if some sort of transition is in the process of taking place with the military, who have probably not been too happy to give up their (nuclear) trump card,’’ said Robert S. Norris, senior research associate at the Natural Resources Defense Council in Washington.
‘‘Now that he may be weakened — or who knows, dead — there may be emerging ... a possible clique of hard-liners who may want to play hardball again,’’ he added.
On the other hand, ‘‘this may be one more negotiating ploy by them,’’ Norris said, alluding to North Korea’s history of escalating tensions during its international negotiations to try to increase its leverage and win concessions.
The Yongbyon nuclear facilities were shut down and then sealed as part of a North Korean pledge to disable its nuclear program. That was meant to be a step toward eventually dismantling the complex in return for diplomatic concessions and energy aid equivalent to 1 million tons of oil under a February 2007 deal with the U.S., South Korea, China, Russia and Japan.
But the accord hit a bump in mid-August when the U.S. refused to remove North Korea from its list of states that sponsor terrorism until the North accepts a plan for verifying a list of nuclear assets that the Pyongyang regime submitted to its negotiating partners earlier.
Yongbyon previously was under IAEA seals in December 2002 when Pyongyang ordered U.N. inspectors out of the country and restarted its nuclear activities, after the unraveling of an earlier deal committing the U.S. to help the North build a peaceful nuclear program.
North Korea quit the Nuclear Nonproliferation Treaty in January 2003. Then on Oct. 9, 2006, it set off an underground test explosion of a nuclear bomb. There was widespread international condemnation, but the U.S. also softened its position and the six-nation deal soon followed.
A U.N. official, who agreed to discuss confidential aspects of the situation only if not quoted by name, said Wednesday that other nuclear sites in North Korea remained under IAEA watch.
The official said that for now agency seals also remained on spent fuel rods that were removed from the Yongbyon nuclear reactor under last year’s deal. Fuel rods can be processed to obtain plutonium for nuclear bombs.
But the official said the three-member IAEA team expected the North would ask soon for the removal of seals from the thousands of fuel rods in storage. More than 60 percent of the rods had already been removed from North Korea under the six-nation deal.
Under the 2007 agreement, scientists began disabling the Yongbyon reactor last November, and in June the North blew up its cooling tower in a dramatic show of commitment to the pact.
Eight of the 11 steps needed to disable the reactor had been completed by July, North Korean officials said.
But later that month, Washington made its request for detailed verification of the process, including soil samples and interviews with scientists. The U.S. pinned one of its concessions — removing North Korea from its list of nations that sponsor terrorism — on verification.
North Korea rejected the demand, saying verification was never part of the deal, and threatened to pull out of the pact if Washington continued pressing for verification.
Associated Press writers Jean Lee in Seoul, South Korea, and Terrence Hunt and Deb Riechmann in Washington contributed to this report.