North Korea on Tuesday ratcheted up its hostile rhetoric by urging all foreign companies and tourists in South Korea to evacuate, saying the two countries are on the verge of nuclear war, while also pulling workers out of a jointly-run factory complex with the South.

Analysts see a direct attack on Seoul as extremely unlikely, and there are no overt signs that North Korea's 1.2 million-man army is readying for war, let alone a nuclear one. South Korea's military has reported missile movements on North Korea's east coast but nothing pointed toward South Korea.

Still, North Korea's earlier warning that it won't be able to guarantee the safety of foreign diplomats after April 10 has raised fears that it will conduct a missile or nuclear test, resulting in U.S. retaliation.

Officials in Seoul say North Korea has already completed preparations for a mid-range missile launch from its east coast tomorrow, the Daily Express reports.

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

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"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" the North, said a statement by the North Korean Asia-Pacific Peace Committee, an organization that deals with regional matters.

The statement is similar to past threats that analysts call an attempt to raise anxiety in foreign capitals. Observers say a torrent of North Korean prophecies of doom and efforts to raise war hysteria are partly to boost the image of young and relatively untested leader Kim Jong Un at home, and to show him as a decisive military leader.

Another reason could be to use threats of war to win Pyongyang-friendly policy changes in Seoul and Washington. Last week, North Korea told foreign diplomats in Pyongyang that it will not be able to guarantee their safety as of Wednesday. It is not clear what the significance of that date is.

Tourists continued to arrive in Pyongyang despite the war hysteria.

Mark Fahey of Sydney, Australia, said he was not concerned about a possible war.

"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."

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, in a typically nationalist rhetoric that most North Koreans use while speaking to the media.

In Seoul, Presidential spokeswoman Kim Haing told reporters that the North Korean warning amounted to "psychological warfare."

"We know that foreigners residing in South Korea as well as our nationals are unfazed," she said.

South Korean President Park Geun-hye, who has sought to re-engage North Korea with dialogue and 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.

On Monday, North Korea said it was suspending work at the Kaesong industrial park near its border, which combines South Korean technology and know-how with North Korea's cheap labor. North Korea pulled out more than 50,000 workers from the complex, the only remaining product of economic cooperation between the two countries that started about a decade ago when relations were much warmer.

South Koreans in Kaesong said North Korean workers stopped showing up at the factory complex on Tuesday morning.

North Koreans who worked an overnight shift at Kaesong were still there, but South Koreans said those scheduled for day shifts didn't show. A North Korean woman at Kaesong said in a telephone call that she planned to return home now that her night shift was done.

Some of the more than 400 South Korean managers still at Kaesong, just north of the Demilitarized Zone, said they planned to stay and watch over their equipment until food ran out.

One worker said he and four other colleagues had been living on instant noodles. "We haven't had any rice since last night. I miss rice," he said Tuesday morning. "We are running out of food. We will stay here until we run out of ramen."

He said he and his colleagues are getting news about Kaesong through South Korean television. There is no Internet connection at Kaesong.

Yoo Ho-yeol, a North Korea expert at Korea University in South Korea, said the North probably will close the park. "North Korea will wait to see what kind of message we will send ... but there is no message that we can send to North Korea," he said.

Yoo said he expects the South Korean managers will be deported, Pyongyang will convert the park for military use, and the fates of the North Korean workers and their families will not be considered. "It's a wrong decision but they won't change it because it's not their top priority," he said.

Another analyst, however, believes North Korea will reopen the complex after South Korea-U.S. drills end in late April. Cheong Seong-chang at the private Sejong Institute in South Korea said the complex depends on raw materials and even electricity from South Korea. He also noted that workers at the complex are paid in U.S. dollars that North Korea would have a hard time replacing because of international sanctions.

Cheong also thinks that although North Korea would put recalled workers on other projects, it would "face a burden that it has to provide the similar quality of livelihood to them. ... There would be voices calling for the normalization of the Kaesong complex."

The Associated Press contributed to this report.