Spy satellites have spotted signs that North Korea may be preparing to transport another long-range missile to a test launch site, South Korean officials said Saturday, as the U.S. defense secretary issued his harshest warning to the North since its recent nuclear test.
"We will not stand idly by as North Korea builds the capability to wreak destruction on any target in Asia — or on us," Defense Secretary Robert Gates told a regional defense meeting in Singapore.
He said the North's nuclear program was a "harbinger of a dark future," but wasn't yet a direct threat.
Since last Monday's nuclear blast, North Korea has test-launched six short-range missiles in a show of force and announced it won't honor the 1953 truce that ended the fighting in the Korean War.
Now, the reclusive communist state appears to be preparing to move a long-range missile by train from a weapons factory near Pyongyang to its northeastern Musudan-ni launch pad, a South Korean Defense Ministry official said.
Images of the movements were captured by U.S. satellites, said the official, who was not allowed to be identified when discussing intelligence matters.
The threat of a long-range missile test comes amid heightened tensions over North Korea's nuclear program.
North Korea, believed to have enough weaponized plutonium for at least six nuclear bombs, walked away from international disarmament negotiations in April in anger over U.N. criticism of a rocket launch Washington and others called a cover for the test of long-range missile technology.
Experts say Pyongyang is working toward mounting a nuclear bomb on a long-range missile, one capable of reaching the U.S.
Gates and the defense ministers of Japan and South Korea said North Korea must not be allowed to continue playing a dangerous game of brinksmanship in hopes of winning aid.
"We must make North Korea clearly recognize that it will not be rewarded for its wrong behaviors," South Korea's Lee Sang-hee said.
Gates said Pyongyang was engaging in familiar tactics. "They create a crisis and the rest of us pay the price to return to the status quo ante."
Preparations for a long-range missile test would take at least two weeks, South Korea's Yonhap news agency reported, citing an unidentified intelligence official.
Officials in Washington said they noticed increased activity at the test site. They spoke on condition of anonymity Friday, saying methods of gathering information about North Korea are sensitive.
Yonhap said the size of the missile was similar to a long-range rocket the North tested in April.
Experts have said the new three-stage rocket has a potential range of more than 4,100 miles (6,700 kilometers), putting Alaska within its striking distance.
The North is likely to fire the missile shortly after the U.N. Security Council adopts a resolution criticizing its recent nuclear test, said Yang Moo-jin, a professor at Seoul's University of North Korean Studies.
A partial draft resolution — obtained Friday by The Associated Press — calls on all countries to immediately enforce sanctions imposed by an earlier U.N. resolution after the North's first nuclear test in 2006.
The sanctions include a partial arms embargo, a ban on luxury goods and ship searches for illegal weapons or material. They have been sporadically implemented, with many of the 192 U.N. member states ignoring them.
The draft would also have the Security Council condemn "in the strongest terms" the recent nuclear test "in flagrant violation and disregard" of the 2006 resolution.
China, wary of instability in the North, has resisted taking strong action and has avoided enforcing past sanctions.
But a Chinese military official was unusually outspoken Saturday in his criticism of the atomic blast.
"As a close neighbor of North Korea, China has expressed a firm opposition and grave concern about the nuclear test," Chinese Lt. Gen. Ma Xiaotian said at the Singapore defense meeting.
North Korea says it conducted the nuclear test in self-defense. Its main Rodong Sinmun newspaper warned Saturday the North "will deal decisive and merciless blows at the enemies who desperately run amok to dare pre-empt an attack on it," according to the official Korean Central News Agency.
Despite the rising tensions, the atmosphere was calm Saturday at the truce village of Panmunjom inside the heavily armed Demilitarized Zone dividing the two Koreas. The area is jointly administered by the U.S.-led United Nations Command and North Korea to supervise the cease-fire.
Some analysts say one of the aims of the North's nuclear and missile tests is to strengthen the regime and boost morale in the impoverished nation.
Rallies were held nationwide to celebrate the "historic" nuclear test, KCNA said, with speakers offering their "ardent congratulations" to scientists and engineers for bolstering the country's dignity.
"They stressed that the successful nuclear test greatly encouraged the Korean people in their dynamic drive for effecting a new great revolutionary surge and dealt telling blows at the U.S. imperialists and their followers keen to stifle" North Korea, KCNA said.