The US has detected activity at potential test sites in North Korea indicating possible preparations for a nuclear test, a US defence official said yesterday, as China urged restraint after the reclusive state said it planned a nuclear test.
US spy satellites have picked up unusual movement of vehicles and other activity at locations that might occur before an underground nuclear test, the US official said, speaking on condition of anonymity because of the sensitivity of the matter.
But the official said the evidence was not definitive and noted that because the North Koreans have never conducted a nuclear test, "we don't really know what we're looking for."
Meanwhile, China, the closest North Korea has to an ally, called for restraint amid rising tensions after Tuesday's announcement by Pyongyang.
"We hope that North Korea will exercise necessary calm and restraint over the nuclear test issue," Foreign Ministry spokesman Liu Jianchao said in a short statement on the ministry's website (www.fmprc.gov.cn).
Mr Liu urged a negotiated settlement, saying countries should "not take actions that escalate tensions".
Russia's and South Korea's foreign ministers denounced as "unacceptable" Pyongyang's plan for a test, the Russian Foreign Ministry said in a statement.
It said Russia's Sergei Lavrov and South Korea's Ban Ki-moon discussed the North Korean situation by telephone. "It was stressed that such steps, which could only aggravate the situation... are unacceptable," the statement said.
The US, France and Japan have all pressed for the issue to be dealt with at the UN. But Beijing wants it resolved through six-country talks set up to end North Korea's nuclear weapons programme.
North Korea has snubbed those talks - involving the two Koreas, China, Japan, Russia and the US - for almost a year.
Pyongyang has refused to return until the US ends a crackdown on North Korean offshore bank accounts, which Washington says is aimed at ending suspected illicit activities and has nothing to do with the six-party process.
Analysts and officials said Pyongyang's nuclear test announcement on Tuesday could well be an attempt to push the US into direct talks about ending the crackdown.
South Korea's Unification Minister, Lee Jong-seok, said he saw a strong element of trying to apply pressure on the US.
"In the event efforts to resume the six-party talks break down, the possibility of a North Korean nuclear test is high," Mr Lee told a parliamentary committee.
Analysts say North Korea probably could make a nuclear weapon but lacks the technology to make it small enough to fit on a missile. They also note that in its July test, North Korea's long-range missile fizzled out just after take-off.
The Stalinist state has triggered diplomatic crises in the past to get its voice heard. Tension on the divided Korean peninsula has risen sharply since July when Pyongyang defied international warnings by test-firing missiles.
North Korea argues that its hand has been forced by what a North Korean diplomat called Washington's "proclamation of war" by threatening economic sanctions.
"These kinds of threats of nuclear war and tensions and pressure by the US compel us to conduct a nuclear test," North Korean embassy spokesman Pak Myong Guk said in Canberra.