North Korean leader Kim Jong-un is visiting China at the invitation of Chinese President Xi Jinping, according to state media in both countries.
The Korean Central News Agency said on Tuesday that Kim departed for his fourth's summit with Xi on Monday afternoon.
Kim, who was accompanied by his wife Ri Sol Ju and top North Korean officials, will stay in China until January 10.
China is North Korea's key diplomatic ally and main source of trade and aid.
Last year, Kim travelled to China three times to meet with Xi before and after summits with US President Donald Trump and South Korean President Moon Jae-in.
The latest trip comes after US and North Korean officials are believed to have met in Vietnam to discuss the location of a second summit between Kim and Trump.
SOURCE: Al Jazeera and news agencies