Kinshasa: A humanitarian plane that was reported missing in eastern Democratic Republic of Congo has crashed into a mountain, a United Nations official said on Tuesday.

"So far the [rescue] helicopter hasn't been able to land. So we still don't know if there are any survivors," an official said.

The plane was carrying 17 passengers and crew and had been on its way from the city of Kisangani to Bukavu on Monday when it lost contact with ground control as it approached for landing.

Rescuers early on Tuesday spotted the wreckage of the 19-seat Beechcraft aircraft around 15 km northwest of the town of Bukavu, on Congo's eastern border with Rwanda.

There was no immediate information about who was travelling on the plane, which was operating under a contract with Air Serv, a US-based organisation.