BEIJING: The United States and China agreed yesterday to make a joint effort to push for the peaceful denuclearization of the Korean peninsula, following weeks of bellicose rhetoric from North Korea and rising tensions in northeast Asia.

US Secretary of State John Kerry had pressed North Korea’s patron China to help defuse sky-high nuclear tensions, telling President Xi Jinping the world was facing a “critical” moment.

The region has been engulfed by threats of nuclear war by Pyongyang in response to UN sanctions imposed over its recent rocket and nuclear tests, and there are fears it could soon fuel the crisis by firing a medium-range missile.

“Mr President, this is obviously a critical time with some very challenging issues,” Kerry told China’s new leader in the Great Hall of the People, on the second leg of an Asian tour that has been swamped by the Korea crisis.

Kerry flew in from talks in South Korea with President Park Geun-Hye, where he offered public support for her plans to initiate some trust-building with the North.

Washington is seeking to persuade Beijing to help rein in the bellicose threats from N. Korean leader Kim Jong-Un, and bring Pyongyang back to the negotiating table over its suspect nuclear program.

Without giving specifics, he said after his meeting with Xi that they “could not have had a more constructive and forward-leaning conversation.”

Earlier in Seoul Kerry said: “I think it’s clear to everybody in the world that no country in the world has as close a relationship or as significant an impact on the DPRK (N. Korea) than China.”

Beijing has backed Pyongyang since the 1950-53 Korean War and could wield tremendous leverage over the isolated communist regime thanks to the vital aid it provides, including almost all of its neighbor’s energy imports.

But analysts say it is wary of pushing too hard for fear of destabilizing N. Korea, which could send waves of hungry refugees flooding into China and ultimately lead to a reunified Korea allied with the United States.

A Chinese city on the border with N. Korea and Russia, Hunchun, held an air raid drill Friday but an official told AFP it was a routine exercise.

Strains in the relationship between the United States and China, the world’s top two economies, have been simmering on an array of diplomatic fronts such as Syria and Iran, as well as trade.