A Soviet-era cargo plane that crashed Wednesday in South Sudan was not authorized to carry passengers, the chief of South Sudan’s Civil Aviation Authority told the Associated Press (AP) Thursday. The plane went down shortly after takeoff from Juba International Airport in the nation's capital, killing at least 36 people.

The captain of the Antonov AN-12 turboprop plane informed the control tower at the Juba airport before taking off that he had 12 passengers and six crew members, Stephen Warikozi told AP. Only one crew member and a child aboard the plane survived the crash. According to AP, it is believed that there were more people aboard the plane than those mentioned by the captain. 

Warikozi reportedly said that, according to the cargo manifest, the plane was carrying 15.5 tons of cargo. The plane was on its way to the northern oil-rich town of Paloch when it crashed close to the White Nile River. The plane belonged to Allied Services Ltd., a logistics and freight company.

A South Sudanese military spokesman told the New York Times that officials were still trying to determine the exact number of deaths. It also remains unclear how many people on the ground were killed by the crash.