The death toll from a fuel tanker explosion in a rural South Sudanese state reached 183 on Friday, a regional official said, as medical staff and volunteers struggled to keep up with the influx of severely burned patients.

At least 60 more people are unaccounted for, said Commissioner Wilson Thomas Yanga of Maridi County in the state of Western Equatoria, where the fuel tanker exploded.

The truck carrying petrol overturned Wednesday outside Maridi and then exploded shortly after hundreds of villagers had gathered around to siphon fuel.

Presidential spokesman Ateny Wek Ateny told The Associated Press said the explosion was an accident caused by a cigarette, but many survivors told the AP that soldiers or police had been shooting guns near the overturned tanker and that may have sparked the explosion. Yanga said an official investigation has not yet started.

At the Maridi hospital, Jan Wynands, a doctor with the International Committee of the Red Cross, said 80 patients had burns covering over 50 percent of their bodies, but he lacked enough equipment. Wynands said he needed catheters, syringes, pain killers and blades for surgery.

The death toll will rise if the patients are not taken to Juba, the national capital, for better care, he added.

About 50 of the injured were evacuated Friday to Juba on flights provided by the Red Cross, the government and the U.N., which sent in a medical team. However, dozens remained in the hospital and in smaller health clinics.

Deadly fuel tanker explosions are common in East Africa, where poor residents living near highways converge around fuel tankers after accidents to steal gas.

In June 2013, 29 people were killed and scores injured in an explosion after a collision between a fuel truck and a passenger van in the Ugandan capital of Kampala.