Kim Jong Un appears in Chinese border city Dandong

North Korean leader Kim Jong Un appears to have arrived in the Chinese border city of Dandong, a government source in Seoul and South Korean media said Saturday.

The Seoul source said Kim arrived via the New Yalu River Bridge, a major border crossing that officially opened last week, 12 years after it was completed. South Korea's Yonhap news agency also reported that Kim had arrived in Dandong earlier in the day, citing an unidentified government source.

The Korea JoongAng Daily, citing an unnamed South Korean government source, said Chinese Premier Li Qiang greeted Kim on arrival. Yonhap said Kim was likely to return to North Korea the same day. South Korea's government said it could not confirm his itinerary.

China is North Korea's largest trading partner and a key source of diplomatic, economic and political support. The four-lane bridge was completed in 2014, but its opening was delayed by a lack of connecting roads and customs facilities on the North Korean side, according to South Korean news reports.

The reported Dandong visit comes as world leaders prepare for November's APEC summit in Shenzhen, raising speculation about a possible meeting between Kim and US President Donald Trump. It also comes before Xi Jinping and other senior Chinese Communist Party officials meet in Beijing on Monday for the party Central Committee's fifth plenary session.

Yang Moo-jin, former president of South Korea's University of North Korean Studies, said Kim may have sought to reaffirm economic cooperation discussed during Xi's visit to North Korea earlier this year and press China to move faster on those commitments. Yang also said Kim may have sought Beijing's support ahead of a possible summit with Trump.