WASHINGTON, Oct 4: The United States has detected activity at potential test sites in North Korea indicating possible preparations for a nuclear test, a U.S. defense official said on Wednesday, as China urged restraint after the reclusive state said it planned a nuclear test.

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.

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.”

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 Wednesday on the ministry’s Web site (www.fmprc.gov.cn).

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 United States, France and Japan have all pressed for the issue to be dealt with at the United Nations. But Beijing wants it resolved through six-country talks set up to end North Korea’s nuclear weapons program.

North Korea has snubbed those talks — involving the two Koreas, China, Japan, Russia and the United States — for almost a year.—Reuters