SEOUL, Feb 28: North Korea, which is reported to have fired up a key nuclear reactor, now looks set to raise tensions further by preparing to start reprocessing plutonium and test a ballistic missile, officials and reports said on Friday.

As South Korea’s new government expressed worries about suspect activity at the Yongbyon reactor, reports from Tokyo and Washington indicated the North might be moving to cross what experts call critical “red lines” in the nuclear standoff.

In Washington, US officials and congressional sources said on Thursday North Korea was continuing to prepare a spent fuel reprocessing plant and could have it operating as a source of weapons-grade plutonium within a month.

Pyongyang’s apparent determination to revive a fully operational nuclear arms programme is a huge headache for the Bush administration, which is on the verge of an invasion of Iraq and has tried to avert a confrontation with North Korea.

Although the diplomatic tensions are apparently unnoticed on the streets of South Korea, the nuclear developments are likely to increase the drumbeat of calls from Seoul, Beijing and Moscow for the United States to talk directly to North Korea.

Washington has resisted this in favour of multilateral diplomatic pressure on Pyongyang.

Russian Foreign Minister Igor Ivanov offered a rare criticism of old ally North Korea on Friday, telling reporters in Beijing: “We think threatening methods are not a solution to the problem.”

Ivanov was responding to questions about fresh signs of North Korean brinkmanship. A major Japanese daily reported on Friday that US satellite photographs and other intelligence indicated North Korea had tested a rocket booster in January for a Taepodong ballistic missile capable of hitting Tokyo.

Japan’s defence minister, Shigeru Ishiba, told reporters he had no information about the report, in the mass-circulation Yomiuri Shimbun, but said Japan did not believe North Korea was about to launch a ballistic missile.

Japanese Foreign Minister Yoriko Kawaguchi spoke to her South Korean and Chinese counterparts by telephone on Friday, urging close coordination between Seoul and Tokyo and calling on Beijing to use its influence with Pyongyang to resolve the crisis.

“It is important to keep the Korean Peninsula free of nuclear weapons,” a Japanese official quoted Chinese Foreign Minister Tang Jiaxuan as saying in reply. “We will play a role so a peaceful and diplomatic resolution can be achieved.”

The South Korean Foreign Ministry indirectly confirmed media reports that the Yongbyon reactor had been restarted.

“Our government voices deep worry and regret at the North Korean reactivation of the five-megawatt reactor which is not only unhelpful to Korean peninsula peace and stability but also violates the nuclear non-proliferation efforts of the international community,” it said.

In Aug 1998, North Korea launched a three-stage Taepodong-1 missile over Japan, demonstrating that major population areas including the capital Tokyo were within its estimated 1,000-km range.

That missile — and longer-range rockets the North is thought to have built but not yet tested — compound worries about the nuclear ambitions of a militant state that also has chemical and biological weapons and the world’s fifth-largest standing army.

On Wednesday, US officials said the North had restarted the Yongbyon reactor, north of Pyongyang, which had been mothballed in 1994.

On Thursday, other US officials told Reuters a steam plant associated with the reprocessing plant had been fired up and chemicals delivered that could be used for reprocessing.

“They could start (reprocessing) on fairly short notice but they haven’t yet,” said one official.

“There also seems to be some effort to make sure they have the necessary chemicals in stock for reprocessing,” another official said. “There have been railroad cars full of chemicals arriving at Yongbyon.”—Reuters