A top North Korean official has said his country will stick to the simultaneous pursuit of nuclear and economic development during his talks with Chinese President Xi Jinping, the North's state media said Thursday.

Ri Su-yong, vice chairman of the North Korean ruling party's central committee, paid a courtesy call on China's leader on Wednesday, the second day of his three-day trip to China.

The Korean Central News Agency said that Ri delivered a verbal message of North Korean leader Kim Jong-un to Xi, which expressed the North's vow to "develop and boost" the two countries' friendship.

Upon briefing Xi on the party congress in early May, Ri reaffirmed that North Korea will stick to Kim's policy of developing nuclear weapons in tandem with boosting the country's moribund economy, commonly known as the "byeongjin" policy, the KCNA said.

"The congress showed that ... the new line of simultaneously developing the two fronts consistently maintained by the Workers' Party of Korea remains unchanged," the report said.

Ri's visit to China is seen as North Korea's attempt to mend frayed ties with China over Pyongyang's nuclear weapons program.

China, North Korea's traditionally ally and economic lifeline, has joined tougher international sanctions aimed at punishing the North for its nuke and missile tests early this year.

It marked the first visit to China by ranking North Korean officials since the communist country conducted its fourth nuclear test in January and launched a long-range rocket in the following month.

China's Xinhua News Agency reported Wednesday that Xi said China "attaches great importance" to its ties with North Korea and Beijing is willing to work with Pyongyang to "reinforce and develop" their relations.

Xi also urged "all parties to remain calm and exercise restraint" on the Korean Peninsula, without mentioning North Korea by name, the report said.

According to the KCNA, Xi said China's government and the communist party remain "unchanged in their policy to protect and develop" the Beijing-Pyongyang relations.

The North's state media delivered Xi's comments on bilateral ties but did not mention the Chinese leader's call for parties on the peninsula to remain calm and show restraint.

The meeting marks the first time in about three years that Xi has met ranking North Korean officials in Beijing. (Yonhap)