The South Sudan Red Cross said on Facebook that it had collected more than 35 bodies at the site. It wasn't clear whether those included people killed on the ground.
Ateny Wek Ateny, a press secretary in the South Sudan President's office, said 18 people were aboard the flight: 12 South Sudanese passengers and six crew members -- five Armenians and one Russian. Three people survived: two South Sudanese passengers and an infant boy less than a year old, Ateny said.
He had said earlier that there were 19 people aboard the plane, 17 of whom died.
The cause of the crash might have been engine failure, Ateny said, although he cautioned this had not been confirmed. He said a witness saw one engine fail before the plane crashed.