Seoul - North Korea on Wednesday sent a top military official to China as a personal envoy of leader Kim Jong-Un, at a time of strained relations with Beijing and ahead of a key China-US summit.
Choe Ryong-Hae, the director of the Korean People's Army politburo, flew to Beijing with a handful of senior military and ruling party officials, the Korean Central News Agency said, highlighting his role "as a special envoy" of the North's young leader.
Choe is believed to be the highest ranking North Korean official to visit China - Pyongyang's sole major ally and chief economic benefactor - since late leader Kim Jong-Il in August 2011.
Kim Jong-Un has never visited since he took over after his father's death in December 2011.
The trip comes at a sensitive time for a relationship which has been sorely tested in recent months by Pyongyang's refusal to heed Beijing's warnings over its nuclear weapons programme.
China has long been the North's chief diplomatic protector, but it sided with the rest of UN Security Council in imposing sanctions after the North's long-range rocket test in December last year, and its nuclear test in February.
Message to Obama
The sanctions triggered a dangerous cycle of escalating military tensions on the Korean peninsula, during which China came under enormous US-led pressure to rein in its wayward ally which was threatening nuclear strikes against the US and South Korea.
Professor Yang Moo-Jin of the University of North Korean Studies in Seoul said the timing of Choe's visit was significant ahead of a scheduled 7-8 June summit between US President Barack Obama and China's new leader Xi Jinping.
And South Korea's new president, Park Geun-Hye, is expected to hold a summit with Xi in Beijing in late June.
"Choe is Kim Jong-Un's closest confidante, so Kim is sending his highest possible envoy to China ahead of the US summit," Yang told AFP.
"This will be Kim's way to deliver his message to Obama concerning peace on the Korean peninsula and the nuclear issue," he added.
Seoul and Washington have held out the prospect of talks with North Korea, but only if it displays a concrete commitment to abandoning its nuclear weapons programme.
The North has made it clear that its nuclear deterrent is not up for negotiation, but observers said Choe might be empowered to offer some assurances or concessions to China.
"He's Kim's top military guy, so clearly the North's nuclear and missile programme will be on the agenda," said Cheong Seong-Chang, an analyst at the Sejong Institute think-tank in Seoul.
"China is looking for some sign of compromise, and Choe might offer an assurance not to conduct any more nuclear tests for now," Cheong said, adding that the North might seek a Kim summit with Xi in exchange.
The bilateral relationship, forged in the 1950-53 Korean War, has weakened significantly over the years, as China's economic transformation has distanced it from the ideological rigidity of the dynastic Kim regime across the border.
In line with UN sanctions, Beijing has moved to tighten Pyongyang's financial operations in China which the international community says are the major conduit for funding its nuclear weapons programme.
The strain in relations was reflected most recently when a Chinese fishing boat with 16 crew was seized by unidentified North Koreans.
The detention caused outrage online in China, with Internet users calling on Beijing to take a tough stance against Pyongyang.
In an editorial on Tuesday before the crew's release, the state-run Global Times, which often reflects nationalist opinion, said Beijing "should let the North Korean side know we are angry".
Cho Han-Bum, an analyst at Korea Institute for National Unification, said Choe's trip would almost certainly include talks on a possible China visit by Kim.
"The North's threats and military brinkmanship during the recent crisis didn't reap much in the way of reward, so Kim needs a boost and a China visit would help cement his legitimacy as leader," Cho said.
But Yoo Ho-Yeol, a North Korea expert at Korea University, said Beijing was unlikely to green light a summit without Pyongyang's commitment to return to six-party talks on its nuclear programme.