PYONGYANG, North Korea (AP) -- After months of ignoring China's warnings to give up its nuclear program, North Korean leader Kim Jong Un sent a high-level confidant to Beijing on Wednesday, in a possible effort to mend strained ties with its most important ally and the latest sign that Pyongyang may be giving diplomacy a chance.
The trip by Vice Marshal Choe Ryong Hae, a senior Workers' Party official and the military's top political officer, is taking place as tensions ease somewhat on the Korean Peninsula after near-daily vows from Pyongyang to attack Washington and Seoul in March and April.
The United States, Japan, South Korea, China and Russia have been busy discussing how best to engage with the North Koreans. Japan sent an envoy to North Korea last week to discuss decades-old abductions of its citizens, a move that has drawn concern among allies of Tokyo who want denuclearization to be the focus of talks.
Choe's visit is the first this year by a top North Korean official to China, which is under pressure from the U.S. and others to rein in its belligerent neighbor. It's also the first since a change of leadership in Beijing, whose new leaders have demonstrated a willingness to work with Washington to harry Pyongyang over its nuclear weapons programs even as stability in North Korea remains the Chinese government's priority.
North Korea also revealed Wednesday that a former defense minister, Kim Kyok Sik, was promoted to chief of the Korean People's Army in the latest in a series of high-level military reshuffles as Kim Jong Un elevates a new generation of military leaders.
Foreign analysts see Choe's trip as part fence-mending mission, part appeal for aid.
The last high-level North Korea-China meeting took place when Chinese Communist Party chief Xi Jinping sent a Politburo member to Pyongyang in November. Weeks later, North Korea launched a long-range rocket, followed by an underground nuclear test in February. That test, the country's third, drew tightened sanctions by the U.N. and United States.
Showing its displeasure with North Korea, China has tightened inspections on cross-border trade and its state banks have halted business with North Korea's Foreign Trade Bank — signs that Beijing is getting serious about enforcing sanctions.
"The North Korean side has been feeling China's pressure," said Ma Xiaojun, a North Korea watcher at the Central Party School, a think tank for the leadership in Beijing.
"Our policies and stance have tended to be tougher and more clearly express our unhappiness and displeasure," said Ma. He added, quoting President Xi, "causing trouble on China's doorstep is not right, and China will not tolerate it."
Choe's priority is to mend ties, Ma said. Immediately upon landing in Beijing, Choe went to see Wang Jiarui, head of the Chinese leadership's international affairs office and long the point man for China's dealings with Pyongyang.
China is impoverished North Korea's economic and diplomatic lifeline, providing nearly all of its fuel and most of its trade. China accounted for 89 percent of North Korea's exports and imports in 2011, according to the most recent figures available from Korea Trade-Investment Promotion Agency in Seoul, South Korea, which collects North Korean trade data.
China and North Korea are jointly developing two special economic zones: Rason on the Korean Peninsula's northeastern tip and Hwanggumphyong, an island in the Yalu River on North Korea's western border.
Chinese Foreign Ministry spokesman Hong Lei reiterated Wednesday that Beijing is committed to seeing North Korea denuclearize while maintaining regional stability — a catchphrase for continued Chinese support for Pyongyang.
Last week, a Japanese envoy traveled to Pyongyang for ongoing discussions about the decades-old abductions of its citizens by North Korea. After the envoy's return, Prime Minister Shinzo Abe said he would be open to holding a summit with Kim Jong Un if it would lead to a breakthrough. The issue is of great importance to Japanese, though when it returned five abduction victims in 2002, North Korea said there were no more living abductees.
Other countries are worried about focusing on Japanese abductions. Glyn Davies, the U.S. special representative for North Korea policy, warned North Korea might be trying to use talks with Japan to drive a wedge between the policies of Tokyo, Washington and Seoul.
During a summit with U.S. President Barack Obama this month, South Korean President Park Geun-hye laid out her policy of building trust with North Korea while remaining firm against provocations. Her office said she may travel to China next month.
China wants security assurances that North Korea will act with less belligerence and make efforts to ease tension, said Daniel Pinkston, an expert on North Korea with the International Crisis Group think tank who is based in Seoul, South Korea.
Because Choe has high-level military and ruling party positions, he can cover a variety of topics and likely will discuss security, normalization of economic ties and possible requests for aid when he meets with Chinese officials, Pinkston said.
Choe is a longtime Kim family friend who often is pictured standing next to the leader, along with Jang Song Thaek, Kim Jong Un's uncle. Jang, a top official now in charge of overseeing the push to expand North Korea's sports industry, visited China in August last year but was not in Wednesday's delegation.
Choe may also try to explain North Korea's recent military moves, including short-range projectile launches off the east coast, said Lee Ji-sue, a North Korea specialist and professor at Myongji University in Seoul.
He may also be paving the way for a visit by Kim Jong Un, who has not been to Beijing since taking power following the December 2011 death of his father, Kim Jong Il. The elder Kim visited China in August 2011.
Meanwhile, among the North Korean officials who went to the tarmac Wednesday to see Choe off was Gen. Kim Kyok Sik, North Korea's newly named chief of the armed forces.
Kim is believed to be commander of the North Korean battalions Seoul accuses of orchestrating two attacks in 2010 that killed 50 South Koreans.
Kim Kyok Sik had served as defense minister until being replaced recently by a little-known general, Jang Jong Nam, in one of several military reshuffles that have taken place since Kim Jong Un took power.
Kim's appointment to head troops suggests North Korea will maintain its hard line toward South Korea, said Han Yong-sup, a professor at Korea National Defense University in Seoul.
Associated Press writers Kim Kwang Hyon in Pyongyang; Sam Kim, Youkyung Lee and Hyung-jin Kim in Seoul, South Korea, Charles Hutzler in Beijing and Eric Talmadge in Tokyo contributed to this report.