South Korean official: North may be preparing to launch missile this week

South Korea's description suggests the weapon in question may be a Musudan-class missile, shown here on display during a 2012 military parade. Photograph: Ed Jones/AFP/Getty Images

By Daniel Arkin, Staff Writer, NBC News

A top South Korean government official announced Sunday that North Korea may launch a missile by Wednesday, at which time the North has said it cannot guarantee the safety of diplomats in the capital of Pyongyang.

The official’s warning came three days after South Korea’s government said that the North had moved at least one medium-range Musudan missile with “considerable range” to the nation’s eastern border, possibly to perform a test launch.

“We’re thoroughly preparing for this, leaving all possibilities open,” said Kim Jang-Soo, South Korea’s national security chief, adding that the North's likely goal is to wrench concessions from Seoul and Washington.

A Musudan missile has an estimated range of up to 2,490 miles, which would make it capable of striking American bases in Guam.

Escalating tensions between the nuclear-armed North and U.S.-aligned South also forced South Korea’s Joint Chiefs of Staff to announce Sunday that the body’s chairman had delayed a visit to Washington, according to The Associated Press.

Meanwhile, the U.S. military said that a top commander in South Korea had also put off a trip to Washington and that the Pentagon had postponed an intercontinental ballistic missile test slated for next week.

The test was "long planned and was never associated with North Korea to begin with," a senior defense official official said, but added that "given recent tensions on the Korean Peninsula, it's prudent and wise to take steps that avoid any misperception or chance of manipulation, so the test has been postponed."

The test was planned for next week at Vandenberg Air Force Base in California. It would have tested the Minuteman 3 ICBM missile, which has a range of about 8,000 miles, although the exact number is classified.

The weekend developments followed the North Korean military’s ominous warning last Thursday that it had been authorized to attack the U.S. using “smaller, lighter and diversified” nuclear weapons — the latest in a series of threats of war against the U.S. since the United Nations imposed tough sanctions in response to the North's third nuclear test in February.

“The moment of explosion is approaching fast,” the North Korean military said in a statement from an unidentified spokesperson.

“No one can say a war will break out in Korea or not and whether it will break out today or tomorrow,” the Thursday statement said.

U.S. Defense Secretary Chuck Hagel said last Wednesday that North Korea’s provocations represent “a real and clear danger and threat” to domestic security and U.S. interests.

“We are doing everything we can ... to defuse that situation on the peninsula,” Hagel said after delivering a speech at the National Defense University at Fort McNair in Washington, D.C.

North Korea has encouraged foreign ambassadors in the capital of Pyongyang to evacuate the country in order to avoid potential hostilities, according to various diplomatic officials.

But South Korea's Kim Jang-Soo suggested to reporters that the North’s warning to diplomats is likely just an attempt to heighten security fears and extract concessions from South Korea and the U.S.

Top embassies, likewise, have appeared to see the North's message as mere rhetoric, according to The Associated Press.

The roughly two dozen countries with embassies in North Korea had not yet announced whether they would evacuate their staffs, the AP reported.

Washington and Seoul want Pyongyang to resume the six-party nuclear talks that it halted in 2009. China, Russia, and Japan were the other key players in the aborted talks.

NBC News' Courtney Kube and Becky Bratu contributed to this report.