A cargo plane has crashed in South Sudan shortly after take-off from Juba International Airport, killing at least 41 people.

The aircraft crashed on the banks of the River Nile around a mile from the airport, according to an official and a Reuters witness.

Presidential spokesman Ateny Wek Ateny said around 20 people were aboard the plane.

Only one crew member and a child survived. 

An unknown number of people were also killed on the ground when the plane came down near a group of fishermen.

"We don't know the number of people that were killed on the ground," Mr Ateny said.

He added that the aircraft was a Russian-made cargo plane bound for the Paloch oil fields in Upper Nile state.

The Russian news agency Interfax, citing a source, said preliminary findings indicate the plane did not belong to any Russian airlines.

A police officer told Reuters at least 41 people died, adding that the death toll is likely to rise.

(Sky News)