An oil tanker exploded in South Sudan, killing more than 100 people after they went around the rig to siphon fuel after it veered off the road, officials said Thursday.

Local government official Charles Kisagna said that at least 100 people were killed and a further 50 people were injured in the explosion, an increase from the 85 cited by presidential spokesman Ateny Wek Ateny when he gave a statement.

At first, provincial governor Patrick Raphael Zamoi cited a higher death toll of 176 with an unconfirmed amount of others critically injured. "People are still dying; they have not assessed the exact number in the hospital," Zamoi said, according to the Associated Press.

The explosion occurred in Maridi in the country's heavily rural Western Equatoria state after the truck veered off the road, Ateny said.

Officials say the locals who noticed the crash began to converge upon the truck, which was "full of petrol", and started siphoned fuel that leaked out of the back. It is believed that one of the people nearby lit a cigarette, causing the explosion, The Independent reported.

Local hospitals have been scrambling to accommodate the injured, but they aren't too hopeful about their chances.

"We don't have medical equipment and these people may not survive because we do not have the facilities to treat the highly burnt people," Kisagna said, according to RT.

Fuel tanker explosions are common in East Africa, where the poor living near highways try to sell gas stolen from tankers that were involved in accidents.

Ateny said that the incident was "an accident" and is unrelated to the ongoing conflict in the region.