Career diplomat Ri Su-yong, one of North Korea's highest-ranking officials, arrived in Beijing on Tuesday in a surprise visit to China that appears to signal the North's attempt to mend soured ties between the allies.

A number of North Korean delegates led by Ri, vice chairman of the North Korean ruling party's Central Committee and the director of the party's International Department, arrived at the Beijing Capital International Airport amid tight security.

Shortly after arriving at the airport, Ri's motorcade of 12 black sedans and one mini bus headed to the Daioyutai State Guesthouse in central Beijing.

Ri served as North Korea's foreign minister until he was promoted as a member of North Korea's politburo during the North's party congress earlier this month.

Ri is expected to meet with Chinese officials, according to diplomatic sources in Beijing.

China's foreign ministry had no immediate comments on Ri's visit to Beijing. In a brief report from Pyongyang, China's official Xinhua news agency said Ri would stay in Beijing for three days.

The visit marks the first time any ranking North Korean official has visited China, North Korea's most import neighbor and economic sponsor, since North Korea conducted its fourth nuclear test in January in defiance of the international community.

Political ties between North Korea and China remain sour as Pyongyang has shown no signs of giving up its nuclear weapons program.

Ri's arrival in Beijing came an hour after South Korean military officials said North Korea attempted and failed to launch an intermediate-range ballistic missile earlier in the day in the latest defiance against U.N. sanctions. The country is expressly barred from launching ballistic missiles.

North Korea was hit by tougher U.N. sanctions in March following the January nuclear test and launch of a long-range rocket in February.

With international pressure over its nuclear weapons program, North Korea wrapped up its first party congress in 36 years earlier this month that cemented leader Kim Jong-un's grip on power and enshrined a policy of simultaneously pursuing nuclear advances and economic development.

Diplomatic sources said Ri could meet with Song Tao, head of the Chinese Communist Party's international department, later in the day.

South Korea's foreign ministry declined to elaborate but said that the government is closely watching the latest developmentsrelated to ties between North Korea and China.

"As strategic cooperative partners, South Korea and Chinamaintain close communication with regards to North Korea affairs," Cho June-hyuck, spokesperson for the ministry, said in a regular press briefing.

"Our government hopes the relations between North Korea and China will advance in a way that could contribute to peace and stability on the Korean Peninsula, get the North to give up its nuclear weapons, and help it emerge as a responsible member of the international community," he added. (Yonhap)