North Koreans restart nuclear reactor

Tensions on the Korean peninsula rose again last night after Pyongyang restarted a reactor at its main nuclear complex in a move that American officials said was the first step towards the production of additional nuclear weapons.

Officials in Washington said sources had revealed that North Korea had recommissioned the nuclear reactor at the Yongbyon site within the past 24 hours. There was no evidence yet that a nuclear fuel reprocessing facility had been reactivated, something experts said would represent a more worrying development.

"North Korea started its nuclear reactor at Yongbyon. It had been closed since 1994," said a Bush administration official. "This is certainly less provocative than starting up the reprocessing facility, but it is significant none the less." The revelation came just days after Colin Powell, the American Secretary of State, confidently reported that North Korea had decided not to reactivate its nuclear programme. Returning to America after attending a ceremony to mark Roh Moo Hyun's succession as the new South Korean President, General Powell said the North had not restarted its nuclear reactor or its reprocessing facility.

Observers said that while five years would be needed for the five-megawatt reactor at Yongbyon to produce enough spent fuel to provide a significant amount of weapons-grade plutonium, North Korea's action was another indication that it was using the threat of promoting its nuclear programme to increase pressure on the Bush administration to hold bilateral talks.

The two countries have been in an increasingly fraught stand-off since October when Pyongyang admitted pursuing a covert programme to produce weapons-grade enriched uranium in contravention of international agreements.

The Bush administration demanded that Kim Jong Il, the North Korean leader, dismantle all his nuclear weapons programmes before any negotiations could take place. The administration believes that North Korea now has one or two nuclear weapons.

American intelligence has been monitoring the position closely to see if North Korea takes an aggressive next step ­ restarting the radiochemistry laboratory at Yongbyon that could within a month produce enough plutonium for five or six nuclear weapons. It would do so by reprocessing fuel rods that were also frozen by the 1994 agreement.

American officials were reported last night to have said they would know if that happened because the process would give off a brownish plume that could be detected by satellites.

Just before Mr Roh gave his inaugural speech, North Korea fired a short-range missile into the Sea of Japan. It landed harmlessly between Japan and the Korean peninsula. Officials from America and South Korea played down the importance of the missile. "It seems to be a fairly innocuous kind of test," General Powell said. "It's a fairly old system."

In previous efforts to increase pressure, North Korea has withdrawn from the nuclear Non-Proliferation Treaty, expelled International Atomic Energy Agency monitors and removed the IAEA monitoring equipment. It also has initiated a uranium-based bomb in violation of its international commitments.

Earlier this week, North Korea warned its citizens to prepare for war, saying the country could be the next American target after Iraq.