Chinese state broadcaster CCTV showed Xi and Kim taking a seaside stroll in the northeastern city of Dalian and holding talks, while the official Xinhua news agency said the two leaders met on Monday and Tuesday.

It was Kim's second visit to China since March, highlighting efforts by the Cold War-era allies to mend ties that have chilled as Beijing has supported UN sanctions over Pyongyang's nuclear activities.

Beijing is keen to avoid being left out in the cold in the wake of Kim's historic summit last month with South Korean President Moon Jae-in and his planned meeting with Trump in June.

"After the first meeting between me and Comrade Chairman (Kim), both China-DPRK relations and the Korean peninsula situation have made positive progress. I feel happy about it," Xi said, according to Xinhua.

For his part, Kim was quoted as saying: "These are the positive outcomes of the historic meeting between me and Comrade General Secretary (Xi)."

Japanese media had earlier shown images of an airplane normally used by North Korean VIPs flying out of Dalian, fuelling speculation that Kim had been in town.