■ Russia is becoming North Korea’s preferred diplomatic partner, forcing the U.S. to turn to Moscow for help.

Reluctance of China opens door for Moscow

WASHINGTON — China’s increasingly icy posture is thrusting Russia forward as North Korea’s preferred diplomatic partner, forcing the Trump administration to turn to Moscow for help in isolating the rogue, nuclear-armed nation.

Beijing’s close ties to Pyongyang have been strained since leader Kim Jong Un ordered the 2013 execution of his uncle who had been the countries’ chief liaison. Since then, the allies once said to be as “close as lips and teeth” have moved further apart over China’s adoption of U.N. sanctions designed to starve North Korea of revenue for its nuclear and missile programs.

But China isn’t North Korea’s only traditionally friendly neighbor.

“Russia could play a useful diplomatic role,” Joseph Yun, the U.S. envoy to North Korea, said in an interview. “If Russia delivers a unified message with the U.S., China, South Korea and Japan that the U.S. is not interested in regime change but rather we want to resolve the WMD issue, they can help better than anyone else to convince them of that.”

Yun said he and Secretary of State Rex Tillerson want Moscow to support the international pressure campaign against North Korea by implementing U.N sanctions, and to urge the isolated, often inscrutable government to engage in diplomatic efforts. Washington also wants to prevent transfers of weapons technology, amid disputed assessments that North Korea might have acquired a high-performance missile engine through illicit networks in Russia or Ukraine.

Like China, Russia has urged a peaceful resolution as Kim and President Donald Trump trade personal insults and threats of war. CIA Director Mike Pompeo recently said Pyongyang is only months away from a nuclear-tipped missile that could strike the United States, a timeline that has raised American alarm and escalated fears of a resumption of the 1950-53 Korean War.

And U.S. Defense Secretary Jim Mattis said Saturday that the threat of nuclear missile attack by North Korea is accelerating.

In the meantime, Russia has cast itself as a potential go-between.

Choe Son-hui, director-general of the North America bureau at North Korea’s Foreign Ministry, has visited Moscow twice in the past month — most recently to attend a nonproliferation conference where she spoke on a panel alongside a nongovernmental American expert and a senior Russian diplomat. Russian Foreign Minister Sergey Lavrov opened the event. Choe also met with Russia’s ambassador to North Korea in Pyongyang last month.

“They seem to be communicating, which is good,” Yun said.

Lee Jin-man The Associated Press U.S. Defense Secretary Jim Mattis, rear right, and South Korean Defense Minister Song Young-moo inspect a guard of honor from a car during a welcome ceremony Saturday at the Defense Ministry in Seoul, South Korea.