North Korea has asked all embassies in Pyongyang to move out staff for their security amid sharp military tensions, but the United States said Friday it has no plans yet to take extraordinary steps with regard to Americans in the communist nation.

The U.S. has no embassy or consulate in North Korea since they have no diplomatic ties. The Swedish Embassy in Pyongyang serves as interim protecting power for the U.S. and provides basic consular services to American citizens.

"We have been in touch with the Swedes, our protecting power in the DPRK (North Korea), because obviously if they were to change their status, we would have to inform American citizens in the DPRK," State Department spokeswoman Victoria Nuland said, briefing reporters. "At this point, we have no reason to believe that they will make any changes." 

She said she has no exact number of U.S. people staying in the North, adding the majority of Americans there are nongovernmental organization workers and occasional tourists. One Korean-American man, in his 40s, has been detained by North Korean security authorities for months.

Nuland confirmed press reports that North Korea's foreign ministry sent such warning messages to foreign diplomatic missions there.

In the notice, the ministry said a war could break out anytime soon and the safety of foreigners is not guaranteed, according to China's official Xinhua News Agency, which has a bureau in Pyongyang. Nuland said the North's message was delivered to every embassy in Pyongyang through a "diplomatic circular." With Pyongyang's intentions unclear, South Korea said it is trying to figure out whether it is bluffing or serious in asking foreign embassies to evacuate their staffs.

The British government said it has no immediate plans to move its officials out of Pyongyang.

Nuland would not be drawn into a question about the possibility that North Korea will carry out its military threats. "I am not in a position to have a crystal ball on that kind of thing," she said. "Obviously, we're going to take prudent precautions."

She noted that the U.S. Embassy in Seoul put out a message to U.S. citizens in South Korea that there is no specific information to suggest an imminent threat to them or related facilities. "So the goal there was to be calming, obviously," she said.

The North has reportedly moved as many as two intermediate or long-range missiles to a launch site along its eastern coast. Earlier this week, the North's military said it received final approval for the use of force.

The White House said Friday it wouldn't be surprised by a missile launch by North Korea, which would be in line with its pattern of belligerence.

"We've obviously seen the reports that North Korea may be making preparations to launch a missile, and we're monitoring this situation closely," press secretary Jay Carney said at a separate press briefing. "And we would not be surprised to see them take such an action."

"It would fit their current pattern of bellicose, unhelpful and unconstructive rhetoric and actions," Carney said. "We urge them to stop with the provocations and to focus instead on meeting their international obligations and feeding their own people."

He added the U.S. is working "constructively with the Russians and the Chinese to try to get them, in particular the Chinese, to use their influence with the North Koreans to persuade them to change their behavior." (YONHAP)