PYONGYANG, North Korea » North Korea on Tuesday (Monday in Hawaii) urged foreign companies and tourists in South Korea to evacuate, saying the two countries are on the verge of a nuclear war. The new warning appeared to be an attempt to scare foreigners into pressing their governments to pressure Washington and Seoul to act to avert a conflict.

Analysts see a direct attack on Seoul as extremely unlikely, and there are no overt signs that North Korea’s army is readying for war, let alone a nuclear one.

Despite the warnings of an impending war, there was no sense of panic in North Korea’s capital, Pyongyang, on Tuesday.

Scores of people of all ages were armed with shovels, not guns, as they planted trees in a forestation campaign. The national flag fluttered across the city as North Korea marked the 20th anniversary of late leader Kim Jong Il’s appointment as chairman of the National Defense Commission. In the evening, women donned traditional Korean dresses and danced in plazas across the country to celebrate.

The call from the Asia-Pacific Peace Committee for foreigners to leave South Korea was the latest in a series of statements aimed at ramping up anxiety abroad about tensions on the peninsula.

"The situation on the Korean Peninsula is inching close to a thermonuclear war due to the evermore undisguised hostile actions of the United States and the South Korean puppet warmongers and their moves for a war against" North Korea, the committee said in a statement carried by state media.

White House spokesman Jay Carney called the statement "more unhelpful rhetoric."

"It is unhelpful, it is concerning, it is provocative," he said.

North Korea has been girding for a showdown with the U.S. and South Korea, its wartime foes, for months. The Korean War ended in 1953 with an armistice, not a peace treaty, leaving the peninsula still technically at war.

In December, North Korea launched a satellite into space on a rocket that Washington and others called a cover for a long-range missile test. The North followed that with an underground nuclear test in February, a step toward mastering the technology for mounting an atomic bomb on a missile.

Tightened U.N. sanctions that followed drew the ire of North Korea, which accused Washington and Seoul of leading the campaign against it. Annual U.S.-South Korean military drills south of the border have further incensed Pyongyang, which sees them as practice for an invasion.

Last week, North Korean leader Kim Jong Un enshrined the pursuit of nuclear weapons — which the North characterizes as a defense against the U.S. — as a national goal, along with improving the economy. North Korea also declared it would restart a mothballed nuclear complex.

Adm. Samuel Locklear, commander of U.S. Pacific Command, told the Senate Armed Services Committee in Washington on Tuesday that he concurred with assessments calling the tension between North Korea and the West the worst since the end of the Korean War.

"The continued advancement of the North’s nuclear and missile programs, its conventional force posture, and its willingness to resort to asymmetric actions as a tool of coercive diplomacy creates an environment marked by the potential for miscalculation," Locklear told the panel.

He said the U.S. military and its allies would be ready if North Korea tries to strike.

Heightening speculation about a provocation, foreign diplomats reported last week that they had been advised by North Korea to consider evacuating by Wednesday.

However, Britain and others said they had no immediate plans to withdraw from Pyongyang.

South Korean President Park Geun-hye, who has sought to re-engage North Korea with dialogue and humanitarian aid since taking office in February, expressed exasperation Tuesday with what she called the "endless vicious cycle" of Seoul answering Pyongyang’s hostile behavior with compromise, only to get more hostility.

U.S. and South Korean defense officials have said they’ve seen nothing to indicate that Pyongyang is preparing for a major military action, and there was no sign of an exodus of foreign companies or tourists from South Korea.

Still, the United States and South Korea have raised their defense postures, as has Japan, which deployed PAC-3 missile interceptors in key locations around Tokyo on Tuesday as a precaution against possible North Korean ballistic missile tests.

In Rome, U.N. Secretary-General Ban Ki-moon described the tensions as "very dangerous" and said that "any small incident caused by miscalculation or misjudgment" may "create an uncontrollable situation."

Also Tuesday, citing the tension, North Korea pulled out more than 50,000 workers from the Kaesong industrial park, which combines South Korean technology and know-how with cheap North Korean labor. It was the first time that production has been shut down at the complex, the only remaining product of economic cooperation between the two countries that began about a decade ago when relations were much warmer.

Other projects from previous eras of cooperation such as reunions of families separated by war and tours to a scenic North Korean mountain have been suspended in recent years.

Though the Foreign Ministry advised foreign embassies to evacuate, tourism officials are continuing to welcome visitors.

National carrier Air Koryo’s daily flight from Beijing was only half full on Tuesday. Flight attendants in red suits and blue scarves artfully kept in place by sparkling brooches betrayed no sense of fear or concern.

Tourist Mark Fahey, a biomedical engineer from Sydney, Australia, said he thought a war was "pretty unlikely."

Fahey, a second-time visitor to North Korea, said he booked his trip to Pyongyang six months ago, eager to see how North Korea might have changed under Kim Jong Un. He said he chose to stick with his plans, suspecting that most of the threats were rhetoric.

"I knew that when I arrived here it would probably be very different to the way it was being reported in the media," he told The Associated Press at Pyongyang airport. He said his family trusts him to make the right judgment, but "my colleagues at work think I am crazy."

He said he took no special precautions. "I haven’t brought anything at all — just a camera," he said with a laugh. But he noted that several other tourists who had been slated to travel with his group had canceled their journeys.

Chu Kang Jin, a Pyongyang resident, said everything is calm in the city.

"Everyone, including me, is determined to turn out as one to fight for national reunification … if the enemies spark a war," he said, using nationalist rhetoric employed by many North Koreans when speaking to the media.

Associated Press writers Hyung-jin Kim in Seoul, South Korea, and Nicole Winfield in Rome contributed to this report.