China has deplored rising tension on the Korean peninsula but said its embassy was operating normally in the North Korean capital and it asked authorities there to ensure its diplomats and other citizens were kept safe.
North Korea, angry about new U.N. sanctions imposed for its third nuclear weapon test in February, has made increasingly strident warnings of an imminent war with South Korea and the United States.
The North has told diplomats to consider leaving Pyongyang because of the tension, but diplomatic missions appeared to view the appeal as more rhetoric and staff have stayed put.
Chinese President Xi Jinping, addressing a forum on the southern island of Hainan, appeared to refer to the tension when he said no country "should be allowed to throw a region and even the whole world into chaos for selfish gain".
Reuters reports that China is North Korea's sole major diplomatic and financial backer, but official statements have reflected a degree of impatience at the actions of authorities under leader Kim Jong-un.
"At present tensions on the Korean peninsula are rising unceasingly, and China expresses grave concern about this," China's Foreign Ministry said in a statement on its website.
A ministry statement quoting Foreign Minister Wang Yi, said Beijing would "not allow troublemaking on China's doorstep".
US delays missile test
The Pentagon has delayed an intercontinental ballistic missile test scheduled for next week.
US defence officials said the Minuteman 3 test out of Vandenberg Air Force Base in California, was put off because of concerns that it could be misinterpreted by North Korea, amid fears of a conflict. It could be postponed till May.
North Korea has issued a series of strong threats since it was sanctioned by the United Nations in March for carrying out another nuclear test.
The BBC reports it has threatened nuclear strikes on the United States, formally declared war on South Korea and pledged to reopen a nuclear reactor in defiance of UN Security Council resolutions.
A Pentagon official said the US wanted to "avoid any misperception or miscalculation" that might result from the test.
The White House said on Friday it would "not be surprised" if the North stages another missile test.
