A senior North Korean foreign ministry official recently visited the northeastern Chinese city of Dalian, informed sources here said Wednesday, amid speculation that leader Kim Jong-un may soon hold another summit with Chinese President Xi Jinping.

Vice Foreign Minister Ri Gil-song visited Beijing last Thursday, when Kim's two-day talks with US President Donald Trump in Hanoi, Vietnam, finished without a deal.

He then traveled unexpectedly to Dalian the following day, according to the sources.

"It's noteworthy that Vice Foreign Minister Ri moved suddenly to Dalian after a visit to Beijing. It's unusual," a source said.

Dalian, a port city quite close to the Korean Peninsula, is where Kim and Xi met in May last year, weeks ahead of the North Korean leader's first summit with Trump in Singapore.

Kim passed through China using his armored train while traveling back and forth between Pyongyang and Hanoi. He did not make a stopover in Beijing, with Xi apparently preoccupied with the country's annual political events, called "two sessions."

Kim and Xi had four rounds of face-to-face talks in 2018.

The fifth summit, if arranged, is expected to take place after March 13, when the meetings of the Chinese People's Political Consultative Conference and National People's Congress are to conclude.

Xi is scheduled to embark on a tour of Europe on March 22. (Yonhap)