The United States and South Korea have drawn up plans for a measured tit-for-tat response to North Korean actions, which will be limited in order to prevent an escalation to broader war, The New York Times reported.

Citing unnamed US officials, the newspaper late Sunday said the new "counter-provocation" plan is calling for an immediate but proportional "response in kind" to North Korea if it decides to launch a ground attack or a missile.

Under the plan, the source of any North Korean attack will be hit with similar weapons, the report said.

If the North Koreans were to shell a South Korean island that had military installations, the plan calls for the South to retaliate quickly with a barrage of artillery of similar intensity, the paper noted.

Kim Jang-Soo, chief national security adviser to South Korea President Park Geun-Hye, said Sunday that North Korea may test-launch a missile this week, as the United States delayed its own missile test due to soaring tensions on the peninsula.

Kim said a test-launch or other provocation could come before or after Wednesday, the date by which the North has suggested that diplomats leave Pyongyang.

If the North launches one of its new Musudan missiles, Pentagon officials said they would be ready to calculate its trajectory within seconds and try to shoot it down if it appeared headed toward impact in South Korea, Japan or Guam, The Times said.

But they planned to do nothing if it were headed toward open water, even if it went over Japan, the paper added.

According to The Times, the officials doubted that North Korean new leader Kim Jung-un would risk aiming the missile at the United States or its allies.

US President Barack Obama has ruled out striking at the missiles while they are on their launchers unless there is evidence they are being fitted with nuclear warheads, which intelligence officials doubt North Korea yet possesses, the paper said.

China seeks N. Korea assurance, warns on 'troublemaking'
Beijing (AFP) April 7, 2013 - China said it had asked North Korea to ensure the safety of its diplomats after a warning that missions should consider evacuating, and that it would not tolerate "troublemaking" on its doorstep.

North Korean authorities on Friday told embassies in Pyongyang that their safety could not be guaranteed if a conflict breaks out, after weeks of escalating threats against the United States and South Korea.

Foreign Ministry spokesman Hong Lei said China "expresses grave concerns" about the growing tensions on the Korean peninsula but that the Chinese embassy was "operating normally".

"The Chinese government has already asked the North Korea side to earnestly ensure the safety of Chinese diplomats in North Korea, in accordance with the Vienna Convention and international laws and practices," he said in a statement on the foreign ministry website Sunday.

Foreign Minister Wang Yi said in a phone conversation with UN Secretary General Ban Ki-moon that there were deep concerns over the situation on the Korean peninsula.

"We oppose provocative words and actions by any party in this region, and will not allow troublemaking on China's doorstep," he said in unusually sharp comments released by the ministry late Saturday.

The New York Times said last week that the US is pressuring China to crack down on the regime in North Korea or face an increased US military presence in the region.

Beijing has been Pyongyang's sole major ally for decades and is its biggest trading partner, providing key energy supplies to the impoverished nation.

Most foreign embassies in Pyongyang have signalled they will remain in the North Korean capital despite the warning.

Tensions have been running high on the Korean peninsula with a series of apocalyptic threats from the North, incensed by fresh UN sanctions imposed after its widely-condemned long-range rocket launch and a third nuclear test.

Ban was "confident the Chinese leadership would also do its best to help calm the situation and help Pyongyang to reverse course", according to a UN statement.