South Sudan faces fuel shortage . (AP Photo/Tony Gutierrez, File)

It is a cruel irony in the world's youngest nation. Ninety-eight percent of South Sudan's economy comes from oil, but the country faces one of its worst fuel crises since civil war broke out in 2013.

South Sudan has Africa's third-largest oil reserves, with 3.5 billion barrels. Based on government figures, current production should bring in hundreds of millions of dollars a year, but some blame corruption for creating nationwide fuel shortages.

People wait in line at gas stations for hours while black market prices soar.

As South Sudan held its first oil and power conference this week, the petroleum minister said the government is moving "aggressively" to produce more oil, with target production of 280,000 barrels per day in the coming year. He said four refineries would be built.