Swedish equipment to test North Korea nuclear claim

"The government believes North Korea actually conducted a nuclear test,"

Unification Minister Lee Jong-Seok told a special parliamentary hearing.

Lee, who is in charge of North Korean affairs, said the government would not yet recognize Pyongyang as a nuclear power until it was known whether the test was successful.

North Korea said Monday it had successfully tested a nuclear bomb.

Seismologists recorded a big blast from a remote northeastern area of the isolated communist country.

US and South Korean authorities have since been trying to verify whether it was a nuclear test and, if so, whether or not it was a success.

The Ministry of Science and Technology said it plans to borrow a xenon nuclide detector from Sweden that can detect minute traces of radioisotopes in the atmosphere.

"The machine, scheduled to arrive in the country on Friday, has been specially developed by Sweden to pick up radioactive particles," it said.

Song Min-Soon, chief presidential security adviser, said earlier it would take about two weeks to pass a comprehensive judgment on the success of North Korea's test.

Unification minister Lee said it was premature to acknowledge the communist state as a nuclear state, something the South has vowed never to tolerate.

"It is not only our basic policy to persuade North Korea to abandon its nuclear ambition, but the analysis (of the success of the test) between South Korea and the United States has yet to be concluded," he said.

The South has responded angrily to the test announcement, with President Roh Moo-Hyun terming it an "unpardonable provocation."

Lee said the government believes the North conducted its test to increase its bargaining power in negotiations with Washington over its nuclear ambitions.

The government "believes the reason North Korea officially announced (its nuclear test) was to secure the status of a de facto nuclear state," Yonhap news agency quoted him as saying.

Since last November, North Korea has boycotted six-nation talks on ending its nuclear programmes, in protest at US pressure on banks which deal with the regime of Kim Jong-Il.

In Washington, the White House said it may not know for "a couple of days"

whether North Korea truly tested a nuclear device, spokesman Tony Snow said Monday.

Snow also suggested that efforts to have the UN Security Council punish the Stalinist regime would not change even if the explosion is found to have been non-nuclear.

"I'm not aware that there is a specific menu for real test/fake test," he said. "Whatever happened, it clearly was a provocative act."

A senior US intelligence official said Monday an explosion of less than one kilotonne in magnitude had been detected but it was not immediately possible to determine whether it was nuclear.

The official, who asked not to be identified, said that first-time nuclear tests historically have been in the several kilotonne range.

Besides seismic data, the US military collects air samples that can be examined for particulates indicative of a nuclear test. North Korean communications and electronic signals also would be analyzed.

"I don't think you can rule out the possibility that he's faking out the world," a defense official said on condition of anonymity, referring to North Korean leader Kim Jong-Il.