Chinese tourists are still visiting Pyongyang from China's border city of Dandong, tourism sources say, even after authorities unofficially halted the tours just ahead of U.S. President Donald Trump's visit to China last month.

A group of 40 Chinese tourists left on Friday from the border city of Dandong to Pyongyang, two sources with direct knowledge of the matter told Reuters, a sign local authorities have not been strongly enforcing curbs on tourist flows.

"This is the largest group to go in from Dandong since the curb," a tour operator said, adding the tourists traveled by train into North Korea for a four-day tour.