WASHINGTON - Plutonium reprocessing activity at a North Korean site has apparently ceased, U.S. officials said Thursday.
It is unclear why the North Koreans stopped work at their reprocessing plant at Yongbyon, the officials said, speaking on the condition of anonymity.
Presumably, they either chose to stop or had technical problems at the plant.
The plant turns spent nuclear fuel rods into plutonium that can be used in nuclear weapons. It's the only one the North Koreans are known to have.
Also Thursday, officials said North Korea appears to be developing a new intermediate-range ballistic missile capable of reaching the United States. The missile hasn't been tested.
The U.S. officials declined to say precisely when activity at the Yongbyon stopped, although other officials had said as recently as last month that low-level reprocessing was under way.
The North Koreans restarted the reactor at Yongbyon in late February. They are also thought to have accessed some 8,000 ready-to-reprocess spent fuel rods that had been in storage.
The North Koreans said they finished reprocessing the rods in April, but Western intelligence officials don't believe them.
Their new missile may have a range of 9,400 miles, a distance within the range of any U.S. state or territory, two U.S. government officials said.
Until now, the limit of North Korea's missile range was thought by U.S. defense experts to have been Alaska or Hawaii for heavier payloads and the western half of the continental United States for lighter payloads.
Whether Pyongyang could reach U.S. targets with a nuclear warhead is not clear; officials are not certain whether their nuclear weapons are small enough to fit on their missiles.