A top South Korean national security official said North Korea may be setting the stage for a missile test or another provocative act with its warning that it soon will be unable to guarantee diplomats' safety in Pyongyang. But he added that the North's clearest objective is to extract concessions from Washington and Seoul.

North Korea's warning last week followed weeks of war threats and other efforts to punish South Korea and the U.S. for ongoing joint military drills, and for their support of U.N. sanctions over Pyongyang's Feb. 12 nuclear test.

The Pentagon has strengthened missile defenses and made other decisions to combat the potential threat. U.S. Gen. Martin Dempsey, the Joint Chiefs of Staff chairman, said Sunday that he doesn't believe North Korea will engage in military action soon, ``but I can't take the chance that it won't.''

Dempsey said the U.S. has been preparing for further provocations or action, ``considering the risk that they may choose to do something'' soon on one of two nationally important anniversaries -- April 15, the birth of North Korean founder Kim Il Sung, and April 25, the creation of the North Korean army.

Tensions between Seoul and Pyongyang led South Korea's Joint Chiefs of Staff to announce Sunday that its chairman had put off a visit to Washington. The U.S. military said its top commander in South Korea had also canceled a trip to Washington.

The South Korean defense minister said Thursday that North Korea had moved a missile with ``considerable range'' to its east coast, possibly to conduct a test launch. His description suggests that the missile could be the Musudan missile, capable of striking American bases in Guam with its estimated range of up to 4,000 kilometers (2,490 miles).

Citing North Korea's suggestion that diplomats leave the country, South Korean President Park Geun-hye's national security director said Pyongyang may be planning a missile launch or another provocation around Wednesday, according to presidential spokeswoman Kim Haing.

During a meeting with other South Korean officials, the official, Kim Jang-Soo, also said the notice to diplomats and other recent North Korean actions are an attempt to stoke security concerns and to force South Korea and the U.S. to offer a dialogue. Washington and Seoul want North Korea to resume the six-party nuclear talks -- which also include China, Russia and Japan -- that it abandoned in 2009.

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

Sweden, which looks after U.S. interests in North Korea because Washington and North Korea lack diplomatic relations, and Brazil have no plans to withdraw any diplomats from Pyongyang at this stage, according to their foreign ministries Sunday. Brazil said it is keeping a close eye on the situation but at this time see no reason to change the decision. There has been no advisory that staff at the Egyptian Embassy will leave or suspend their work.

Without specifically mentioning North Korea, Chinese President Xi Jinping said Sunday that no one country should be allowed to upset world peace.

``The international community should advocate the vision of comprehensive security and cooperative security, so as to turn the global village into a big stage for common development rather than an arena where gladiators fight each other. And no one should be allowed to throw the region, or even the whole world, into chaos for selfish gains,'' Xi said Sunday at the Boao Forum for Asia, a China-sponsored talk shop for the global elite. He said China would work to reduce tensions over regional hotspots.

Seoul and Washington are taking the threats seriously, though they say they have seen no signs that Pyongyang is preparing for a large-scale attack.

Kim Jang-soo said the North would face ``severalfold damages'' for any hostilities. Since 2010, when attacks Seoul blames on North Korea killed 50 people, South Korea has vowed to aggressively respond to any future attack. 

South Korean Joint Chiefs of Staff Chairman Gen. Jung Seung-jo had planned to meet with his U.S. counterpart, Gen. Martin Dempsey, in Washington on April 16 for regular talks. But tensions on the Korean Peninsula are so high that Jung cannot take a long trip away from South Korea, so the meeting will be rescheduled, a South Korean Joint Chiefs officer said Sunday. The officer spoke on condition of anonymity, citing office policy.

The top U.S. military commander in South Korea, Gen. James Thurman, will not make a planned trip to Washington this week to testify before Congress because of tensions with North Korea. In an email Sunday to The Associated Press, Army Col. Amy Hannah said Thurman would remain in Seoul as ``a prudent measure.'' He was scheduled to testify on Tuesday and Wednesday.

The U.S. Defense Department has delayed an intercontinental ballistic missile test that had been planned for this week because of concerns the launch could be misinterpreted and exacerbate the Korean crisis, a senior defense official told The Associated Press.

Defense Secretary Chuck Hagel decided to delay the test at an Air Force base in California until sometime next month, the official said Saturday. The official was not authorized to speak publicly about the test delay and requested anonymity.

In recent weeks, the U.S. has followed provocations from North Korea with shows of force connected to the joint exercises with South Korea. It has sent nuclear capable B-2 and B-52 bombers and stealth F-22 fighters to participate in the drills.

In addition, the U.S. said last week that two of the Navy's missile-defense ships were moved closer to the Korean Peninsula, and a land-based missile-defense system is being deployed to the Pacific territory of Guam later this month. The Pentagon last month announced longer-term plans to strengthen its U.S.-based missile defenses.

The U.S. military also is considering deploying an intelligence drone at the Misawa Air Base in northern Japan to step up surveillance of North Korea, a Japanese Defense Ministry official said Sunday.

Three Global Hawk surveillance planes are deployed on Guam and one of them is being considered for deployment in Japan, the official said on condition of anonymity because the official was not authorized to speak about the issue.

Also on Sunday, Iran's foreign ministry urged all sides to exercise restraint and not to move toward ``provocative behavior.''

``We think that the event that is intensifying between North Korea, South Korea and the United states  should be controlled as soon as possible,'' Iran's semi-official Mehr news agency quoted foreign ministry spokesman Ramin Mehmanparast as saying. ``Both parties should not move toward a corner in which there is a threatening climate.''

Mehmanparast's comments came two days after Gen. Masoud Jazayeri, the deputy chief of staff of Iran's armed forces, reportedly said that North Korea had ``no choice except confronting the U.S.''

North Korea successfully shot a satellite into space in December and conducted its third nuclear test in February. It has threatened to launch a nuclear attack on the United States, though many analysts say the North hasn't achieved the technology to manufacture a miniaturized nuclear warhead that could fit on a long-range missile capable of hitting the U.S.

North Korea also raised tensions Wednesday when it barred South Koreans and supply trucks from entering the Kaesong industrial complex, where South Korean companies have employed thousands of North Korean workers for the past decade.

North Korea is not forcing South Korean managers to leave the factory complex, and nearly 520 of them remained at Kaesong on Sunday. But the entry ban at the park, the last remaining inter-Korean rapprochement project, is posing a serious challenge to many of the more than 120 South Korean firms there because they are running out of raw materials and are short on replacement workers.

Nine more firms, including food and textile companies, have stopped operations at Kaesong, bringing to 13 the total number of companies that have done so, South Korea's Unification Ministry said in a statement Sunday.

North Korea briefly restricted the heavily fortified border crossing at Kaesong in 2009 -- also during South Korea-U.S. drills -- but manufacturers fear the current border shutdown could last longer. (AP)