WASHINGTON, April 8 – The White House on Monday welcomed efforts by Russia and China to ease the crisis with North Korea, after pushing both nations to use their influence to change the isolated state's behavior.

Washington last week had urged China and Russia to exert their leverage following several bellicose actions and statements from Pyongyang under its untested new leader Kim Jong-Un, which sent regional tensions soaring.

"We welcome efforts by Beijing and Moscow to encourage Pyongyang to refrain from provocative rhetoric and threats," said White House spokesman Jay Carney on Monday.

"We will continue to work with our Chinese, Russian and other partners to get North Korea to abide by its international obligations," he added.

Deputy Defense Secretary Ash Carter, meanwhile, said the US military was closely tracking the situation but voiced hope China would persuade North Korea to pull back from confrontation.

"I do think that China could play and I do wish that they would play a larger role in influencing North Korea to stop these provocations," Carter said at an event at a Washington think tank.

"China has more influence than any other country on North Korea," he said at the Center for Strategic and International Studies.

The New York Times reported late Friday that the United States had pressured China's new President Xi Jinping to crack down on Kim's regime, or face an increased American military presence in the region.

Citing unnamed administration officials, the newspaper said the recent US exchanges with China included a phone call from President Barack Obama to Xi.

Chinese 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 foreign ministry late Saturday.

On Monday, Russian President Vladimir Putin warned that any conflict on the Korean peninsula would be worse than the 1986 Chernobyl nuclear disaster and praised Washington for delaying a ballistic missile test.

"We should thank the United States for this important step," he said in Hanover, Germany.

"I hope it will be noticed by our partners including North Korea and that everyone will calm down and work together to seek a solution to the various problems."

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.

The Pentagon is not ready to dismiss North Korea's threats, despite recognizing Pyongyang's tendency to engage in bellicose language, Carter said.

"North Koreans have been determined to create a crisis atmosphere, but just because they have a habit of indulging in extreme rhetoric doesn't mean we don't take the situation very seriously," Carter said.