DANDONG (China) (AFP) - A key border crossing between North Korea and China been closed to tourist groups, a Chinese official said on Wednesday as nuclear tensions mounted, but business travel was allowed to continue.

An official at the Dandong Border Office, who declined to give his name, told AFP: "Travel agencies are not allowed to take tourist groups to go there, since the North Korean government is now asking foreign people to leave. As far as I know, business people can enter and leave North Korea freely."