Authorities in São Tomé and Príncipe are searching for a plane with an American pilot that disappeared off the coast of the African island country.

According to U.S. diplomats and aviation officials involved with the search, the plane was approaching São Tomé late Sunday when it abruptly ceased communication with local air traffic controllers.

Controllers say the plane went missing about 14 kilometers out from the airport, and may have been caught up in heavy thunderstorms to the southeast.

The pilot was the only person on board the plane, a Beechcraft 1900 turboprop that seats up to 18 people.  

The pilot, whose name has not been released, was on a flight from Namibia to Mali.

Fishing vessels and residents of São Tomé and Príncipe and nearby Gabon have been asked to alert authorities if they see any signs of the aircraft.