Countries in northeast Asia remained on edge Wednesday amid warnings from U.S. and South Korean officials that North Korea could carry out a missile test at any point.

Japan has deployed missile defense systems around Tokyo, some Chinese tour groups have canceled visits to North Korea, and U.S. radars and satellites are trained on an area of the Korean east coast where Kim Jong Un's regime is believed to have prepared mobile ballistic missiles for a possible test launch.

After weeks of belligerent threats and provocative gestures from Pyongyang, the situation on the Korean Peninsula is fragile.

Adm. Samuel J. Locklear, the top U.S. commander in the Pacific, said Tuesday that he couldn't recall a time of greater tension in the region since the end of the Korean War in the 1950s.

Before the two controversial long-range rocket launches that North Korea carried out last year, the reclusive regime gave ample warning to the world. But it is keeping everyone guessing about what it might do this time around.

Intelligence suggests that North Korea may be planning "multiple missile launches" in the coming days beyond two Musudan mobile missiles it has placed along its east coast, a senior Pentagon official told CNN on Wednesday.

The official did not have specifics on the numbers of other missiles and launchers spotted on U.S. imagery.

The official said the North Koreans are military "masters of deception" and may have planned all along to focus the world's attention on the Musudans while they plan multiple launches of other missiles, which is a tactic they have used in the past.

But the United States is less troubled about the movement of the other missile launchers, a second Pentagon official told CNN.

"We've been seeing some launchers moving around. These are smaller and don't cause us as much concerns," the official said. "We think these movements are within seasonal norms for their exercises."

But he didn't discount the possibility that they might launch some of those, as they often do.

South Korean Foreign Minister Yun Byung-se said at a parliamentary hearing Wednesday that "according to intelligence obtained by our side and the U.S., the possibility of a missile launch by North Korea is very high," the semiofficial South Korean news agency Yonhap reported.

The Musudan is an untested weapon that he said has a range as far as 3,500 kilometers (2,175 miles). That would mean it could reach as far as Guam, a Western Pacific territory that is home to U.S. naval and air bases and where the United States recently said it was placing missile defense systems.

After any launch, U.S. satellites and radars in the region would be able to calculate the trajectory of missiles within minutes and quickly conclude whether they are on a test path headed for open ocean or potentially headed for land areas such as Japan.

The United States and Japan would then have to decide whether to try to shoot the missiles down, U.S. officials say.

Russian Foreign Minister Sergei Lavrov on Wednesday told CNN that despite being an ally of North Korea, it stands with the United States.

"On North Korea, we have no differences with the United States. One just shouldn't scare anyone with military maneuvers and there's a chance things might calm down," he said.

A launch without warning?

Yun said he was basing his assessment on South Korean and U.S. intelligence. On Tuesday, a U.S. official said that the American government believes a test launch could happen at any time and without North Korea issuing a standard notice to commercial aviation and maritime shipping that would warn planes and vessels to stay away from the missile's path.

The official, who declined to be named because of the sensitivity of the information, cautioned that most of the information comes from satellite imagery, so it's impossible to reach a definitive conclusion because the United States cannot gather information on the ground.

He said the launch could be "imminent" but also cautioned that the United States "simply doesn't know." Based on what the United States has seen, the belief is that the missiles have received their liquid fuel and are ready for launch.

Speaking at a Senate Armed Services hearing Tuesday, Locklear said the U.S. military would not want to shoot down a North Korean missile whose trajectory would send it into the open sea. But he said if the missile's path appeared to threaten a U.S. ally, such as Japan, interceptor missiles could be used to try to bring it down.

Japan's deployment of missile defenses in Tokyo follows similar measures taken ahead of the North's rocket launches last year.

Since the U.N. Security Council voted last month to impose new sanctions on Kim's regime over the latest North Korean nuclear test, Pyongyang has kept up a steady flow of words and acts that could give the impression of a nation heading inexorably toward conflict.

On Tuesday, it advised foreigners in South Korea to secure shelter or evacuate the country in case of hostilities on the Korean Peninsula, the latest in a string of ominous warnings.

It also kept more than 50,000 of its workers from an industrial complex jointly operated with South Korea, which had been a key symbol of cooperation between the two countries.

'Holiday atmosphere' inside North Korea

But on the same day, state media published articles that described festive events and international visits, suggesting a much less fraught situation inside North Korea.

The state-run Korean Central News Agency (KCNA) reported that various sporting events were happening or scheduled to take place to mark the 101st anniversary next week of the birth of Kim Il Sung, the founder of North Korea and the grandfather of Kim Jong Un.

"The ongoing sports tournaments make the country seethe with holiday atmosphere," KCNA said. Kim Il Sung's birthday, known as the Day of the Sun, is a major public holiday in North Korea.

The planned events include an international marathon Sunday in Pyongyang in which runners from North Korea and other countries will participate. KCNA also noted Tuesday the arrival by plane in North Korea of a delegation from the Japan-Korea Society for Scientific and Educational Interchange.

Such visits sit strangely alongside the North's warning last week to foreign diplomats in Pyongyang that it wouldn't be able to guarantee their safety in the event of a conflict.

Some North Korea watchers have observed that the regime's domestic propaganda has focused recently on efforts to promote economic development, while the bellicose threats appear targeted primarily at a foreign audience.

Varying levels of concern

The angry rhetoric has also failed to alarm South Koreans, who have lived through decades of North Korean bombast. Residents of Seoul have continued to go unflappably about their daily business.

"South Korea has been living under such threats from the past, and we are always prepared for it," South Korean Unification Minister Ryoo Kihl-jae told CNN on Wednesday. He called the current climate "a very ordinary situation."

"North Korea may launch missiles at any time, and our military is fully prepared for it," he said.

But the North's fiery words appear to have had an effect on the American public, with 41% of those surveyed saying they see the reclusive nation as an immediate threat to the United States, according to a recent CNN/ORC International poll.

That's up 13 percentage points in less than a month, CNN Polling Director Keating Holland said.

"If North Korean leader Kim Jong Un wanted to get the attention of the American public, his strategy is starting to work," Holland said.

Andrei Lankov, a professor of history at Kookmin University in Seoul, noted the varying levels of concern in an opinion article for The New York Times published Tuesday.

"The farther one is from the Korean Peninsula, the more one will find people worried about the recent developments here," he said.

The tense situation does appear to have prompted some Chinese tour groups to call off upcoming trips to North Korea.

Hong Lei, a spokesman for the Chinese Foreign Ministry, said Wednesday that some agencies and tourists had canceled plans, but he said the Chinese-North Korean border continued to operate normally.

Western tourism agencies that organize visits to North Korea haven't so far reported any changes to their activities.

A troubled industrial zone

The most tangible signs of disruption are in the Kaesong Industrial Complex, the manufacturing zone on the North Korean side of the border where more than 120 South Korean companies operate.

Last week, the North started blocking South Korean personnel from crossing the border back into the complex. And this week, it said it was pulling out the more than 50,000 North Koreans who work inside the zone and temporarily suspending activities there.

It had blocked the border crossing previously, in 2009, but pulling out the workers was a new step.

As of Wednesday lunchtime, only a few hundred South Koreans remained inside the complex, according to South Korean authorities, down from more than 800 before the North started restricting entry.

Also on Wednesday, South Korea accused the North of carrying out a wave of cyberattacks that paralyzed the networks of major South Korean banks and broadcasters last month. It is the first time that Seoul has formally pointed the finger at Pyongyang for the hacking, which affected more than 48,000 computers.