China‘s vice president will visit North Korea this week for Korean War commemorations following a period of strained relations between the communist neighbors.

Vice President Li Yuanchao will be the highest ranking Chinese official to visit North Korea since Kim Jong-un took over as leader of the impoverished hard-line communist state upon his father’s death in December 2011.

The trip lasting Thursday through Sunday affirms a warming trend in relations between a deeply isolated Pyongyang and Beijing, its only real ally and key source of economic assistance.

The statement posted Wednesday on the Chinese Foreign Ministry‘s website said Li will visit for 60th anniversary commemorations of the end of the 1950-53 Korean War, in which China fought on the North’s side against U.N. forces led by the United States.

That shared history, in which troops sent by Mao Zedong likely saved the North Korean regime from annihilation, has been the default fallback for the sides through periods of ambivalence bordering on animosity.

Most recently, Beijing was deeply offended by Pyongyang‘s actions following Kim’s ascension, including conducting rocket launches, a nuclear test and other saber-rattling that spiked tensions with South Korea and the U.S.

Beijing considered the moves an affront to its interests in regional stability and showed its displeasure by joining with the U.S. to back U.N. sanctions and cut off dealings with North Korea‘s Foreign Trade Bank.

North Korea also frustrated Beijing by refusing to agree to high-level meetings and incensed the Chinese public after a Chinese fishing crew was detained.

The bad blood led to an unusual half-year gap in high-level contacts that ended in May when Pyongyang dispatched one of Kim’s close allies to Beijing to reaffirm to close traditional ties and commit North Korea to eventually rejoining six-nation nuclear disarmament talks hosted by Beijing.

Despite the improvement in ties, policy toward the North remains one of the most debated issues among the Chinese foreign relations establishment, with some scholars going so far as calling for Beijing to end its economic and diplomatic support for Pyongyang.

Yet North Korea remains a crucial buffer between China and the 28,000 U.S. troops based in South Korea, and Beijing wins credit internationally by exercising what influence it has over the regime to moderate its behavior.

That means China will retain its support for Pyongyang, even while becoming more critical of some of its actions, wrote Ren Xiao, director of the Center for the Study of Chinese Foreign Policy at Fudan University in Shanghai.

"China is bound to adjust its North Korean policies, but it doesn‘t mean Beijing will side with the U.S., Japan, and South Korea. Rather, it will respond to the North’s extreme moves that offend China‘s interests and will make the North correct those moves," Ren wrote in a recent essay for the Washington-based Center for Strategic and International Studies.

Although the Foreign Ministry gave no details, Li is almost certain to meet with Kim and other top North Korean readers, since to not do so would almost certainly be taken as a snub.

Those discussions are likely to focus on Beijing’s much cherished goal of coaxing Pyongyang back to the nuclear talks that also involve the United States, South Korea, Russia and Japan.

There has been no significant progress toward resuming the long-stalled discussions since the North Korean envoy‘s visit to Beijing, while the North has devoted its attention instead to bilateral talks on restoring exchanges with South Korea.

North Korea walked away from the six-party nuclear disarmament talks in 2009 over disagreements on how to verify steps it was meant to take to end its nuclear programs.

Since its third nuclear test in February, North Korea has said any future diplomatic talks would have to recognize it as a nuclear power.

Washington has said it won’t accept that and demands that talks be based on past commitments by the North to abandon its nuclear programs. (AP)