An airport official in South Sudan says a cargo plane crash in the capital, Juba, killed five crew members Tuesday.

Axar.az reports that it was not immediately clear what caused the plane belonging to Optimum Aviation Ltd. to crash shortly after takeoff from Juba International Airport en route to Maban county, located in Upper Nile state in the country’s north.

“Five people, including pilot and crew members, lost their lives,” airport director Kur Kuol told The Associated Press. He said two Russian nationals and South Sudanese nationals were killed.

The chartered Antonov was carrying cargo that included fuel.