US Secretary of State John Kerry has arrived in Beijing to urge China’s leaders to use their influence on North Korea to reduce regional tensions.

Speaking to China’s President Xi Jinping, John Kerry said the world was facing a “critical time”.

John Kerry’s four-day tour of Asia comes amid speculation that North Korea is preparing for a missile launch.

The secretary has said that as the closest ally of Pyongyang China should “put some teeth” into urging restraint.

A flurry of warlike statements from Pyongyang has prompted speculation that it might launch a missile – possibly on April 15, when the country marks the 101st birthday of the nation’s founder and former leader, Kim Il-sung.

North Korea has reportedly moved at least two Musudan ballistic missiles to its east coast, but on Saturday, South Korea’s Yonhap news agency quoted officials in Seoul as saying that no new movement of the mobile launchers had been detected for two days.

US Secretary of State John Kerry has arrived in Beijing to urge China’s leaders to use their influence on North Korea to reduce regional tensions

Since the UN imposed fresh sanctions on North Korea in February, its leadership has promised to restart a mothballed nuclear reactor, has shut an emergency military hotline to South Korea, and has urged diplomatic staff to leave, saying it cannot guarantee their safety.

North Korea says it has also been angered by joint US-South Korean military exercises.

Though North Korean rhetoric has been more bellicose than usual, analysts say it fits a long-standing pattern, and may be intended to boost the popularity of Kim Jong-un, who came to power last year.

After arriving in Beijing on Saturday and holding talks with his counterpart, Wang Yi, John Kerry told Xi Jinping the world was facing “a critical time with some very challenging issues”.

Among them were Korean tensions but also “the challenge of Iran and nuclear weapons, Syria and the Middle East, and economies around the world that are in need of a boost”, he said.

John Kerry later said he and Xi Jinping had had “constructive and forward-leaning” talks, without giving further details, Reuters reports.

On Friday, during a visit to the South Korean capital, Seoul, John Kerry said the US would protect itself and its allies, and that his talks in Beijing would aim to “lay out a path that will defuse this tension”.

He said no country had a closer relationship with Pyongyang than China.

Beijing, like Washington, wanted denuclearization on the peninsula, he said, adding: “If that’s your policy, you’ve got to put some teeth into it.”

He warned North Korea against any missile launch, saying it would be a “provocation and unwanted act” which would further isolate North Korea and its people who, he said “are desperate for food, not missile launches”.

China is North Korea’s only ally and major trading partner, but has grown increasingly frustrated with its growing belligerence.

John Kerry will be pressuring China to use its economic leverage to force its rebellious ally to tone down its threats.

But in turn, China is pushing the US to do more to make North Korea feel secure.

In Seoul, John Kerry voiced his support for the vision of a reunified Korean peninsula – so far a development neither Chinese nor Korean leadership want to see.

Russia has also expressed growing concern over North Korea and said on Friday that it had issued “an urgent appeal” to Pyongyang “to refrain from actions which could lead to further escalation of tension”.

US officials including John Kerry have been playing down a leaked report from the Defense Intelligence Agency (DIA) which warned there was “moderate” confidence Pyongyang had developed the technology to mount a nuclear warhead on a missile.

White House spokesman Jay Carney said Pyongyang had “not demonstrated the capability to deploy a nuclear-armed missile”.

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