North Korea says it has removed all remaining spent nuclear fuel rods from its main reactor, a move that could allow it to reprocess the fuel and extract weapons-grade plutonium.

The country's official news agency quoted a North Korean official as saying technicians have successfully removed 8,000 spent fuel rods from the Yongbyon nuclear plant.

Security analyst Tim Savage of the International Crisis Group research organization in Seoul, says the action seems for now to be a provocative move by North Korea, though not an immediate danger.

"It is going to take them a couple of months to reprocess it. So, it is adding fuel to the fire, but it is not anything spectacularly new," he said.

Pyongyang's announcement follows reports from Washington that North Korea may be preparing for a nuclear test.

The new U.S. ambassador to Japan, Thomas Schieffer, said a test would be a serious blow to the process of bringing the North back to multi-party negotiations on ending its nuclear program.