Updated

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 hardline 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 its only real ally and key source of economic assistance.

The statement posted Wednesday on the 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.

Beijing had been deeply offended by Pyongyang's actions following Kim's ascension, including conducting rocket launches, a nuclear test and other saber-rattling — spiking 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.

That 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.

Yet, there has been no significant progress toward resuming the long-stalled discussions since the envoy's visit, while the North has devoted its attention to talks 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 says it won't accept that and demands that talks be based on past commitments by the North to abandon its nuclear programs.