North Korea's Vice-Marshal Choe Ryong Hae, who was appointed as a "special envoy" for North Korean leader Kim Jong Un, left Pyongyang for China on May 22, 2013. His trip comes at a rocky time in ties between the allies. (Jon Chol Jin/AP)

A key North Korean military official arrived in Beijing on Wednesday as a “special envoy” of leader Kim Jong Un, state-run media reported. The trip comes amid new signs of strain between the traditional allies.

Choe Ryong Hae, who holds several top Workers’ Party positions and serves as vice marshal of the Korean People’s Army, met with Wang Jiarui, a senior official of the Chinese Communist Party,according to China’s official Xinhua News Agency. Neither Beijing nor Pyongyang provided details of the meeting or indicated the length of Choe’s stay.

Choe’s visit marks the first trip to China by a high-level North Korean since August and could signal an attempted detente after the North spent months stoking tensions in the region — and frustrating China.

The North ignored China’s warnings not to carry out a February nuclear test. More recently, itseized the crew of a Chinese fishing boat, holding them for more than two weeks while trying to extract a ransom.

Analysts say longtime allies Beijing and Pyongyang have increasingly different visions of how they should get along. The North wants to test weapons and alarm its neighbors while still collecting aid and investment from China. China prefers the North to be peaceful and compliant and has recently signaled a new willingness to pressure the Pyongyang government to change its behavior.

China supported U.N. Security Council sanctions after the February nuclear test. Earlier this month, the state-run Bank of China cut off dealings with North Korea’s primary foreign-exchange bank, a conduit for funding the North’s weapons program.

Choe’s trip could represent an effort to repair frayed ties, although the North’s government-controlled media did not elaborate on its purpose.

Observers who monitor the police state say Choe is among Kim’s closest lieutenants. Since Kim took over as head of state after the death of his father in December 2011, Choe has received numerous high-profile titles, giving him power on par with that of Jang Song Thaek and Kim Kyong Hui, Kim’s aunt and uncle.

His visit to China could provide the United States and South Korea with some indirect insight into the North’s young leader and his interest in dialogue. President Obama and South Korean President Park Geun-hye have both scheduled summits in June with Chinese leader Xi Jinping.

Kim himself has not traveled to China since becoming North Korea’s leader.

In recent years, U.S. and South Korean officials have urged China to increase pressure on the North to curb its weapons program.

The international community must speak to North Korea with “one voice,” Park said during a trip to Washington this month, adding that countries must tell the North’s leaders “they have no choice but to change.”