Baku. 18 September. REPORT.AZ/ The tanker had veered off the road in Maridi, Western Equatoria state, and local residents were siphoning off the fuel when the vehicle exploded, they said.
Report informs referring to BBC, at least 50 people are reported to have been injured.
Local hospitals have been overwhelmed, and state officials have appealed to the Red Cross and the UN for help.
The tanker was travelling from the capital Juba and was close to Maridi, some 250km (155 miles) away, when it came off the road and overturned.
Maradi county commissioner Wilson Thomas Yanga told the BBC's Focus on Africa programme that while the driver went to the nearest town to get help, local residents had descended on the tanker to collect some of the petrol it contained.
He said it was not yet clear what caused the explosion.
Mr Yanga confirmed the death toll had risen to 176, and said officials feared the true number of wounded was not yet known as many may have fled the scene.