"Eighty five people are confirmed dead by the local authorities," Presidential spokesman Ateny Wek Ateny told reporters a day after the incident occurred. At least 50 more people had been injured, he added, indicating that the death toll could rise.

The explosion took place near Maridi in the country's southwest on Wednesday when the tanker, traveling from Juba to Yambio, overturned and began leaking. According to Ateny, local residents were trying to siphon off some petrol when somebody lit a cigarette, setting off the explosion.

The injured were taken to local hospitals, but chances of their survival were low. "We don't have medical equipment and these people may not survive because we do not have facilities to treat highly burnt people," Charles Kisagna, information minister for the state of Western Equatoria, told journalists.

"This was an accident," Ateny said, arguing that the blast had nothing to do with the conflict between government forces and rebel fighters that has been going on since 2013. A new truce deal this year has not been entirely effective.

South Sudan, one of the world's poorest countries, has almost no tarmac roads and fuel tankers often travel along poorly maintained paths to reach far-flung communities.

mg/msh (dpa, AP, Reuters)