Battered by an economic crisis, Venezuelans are used to waiting in long lines for scarce goods, but many found themselves queuing Thursday for something the ailing oil giant was supposed to have in spades: gasoline.
Drivers had to wait more than an hour to fill up at many gas stations in Caracas and several other cities after supplies were mysteriously disrupted.
AFP correspondents saw some drivers pushing their vehicles to the pump after running out of fuel while waiting in line.
"There's no reason an oil-producing country should have a gasoline shortage," said irate retiree Jesus Ascanio at a gas station on the capital's east side.
"I've been here for almost an hour from that corner to here. But at least now I'm in the line."
Shortages also hit the western states of Zulia and Tachira, where some gas stations suspended sales.
State oil company PDVSA sought to calm people's nerves, saying it "guarantees the supply of fuel across the country" -- but it offered little explanation for the shortages.
The vice president for sales and supply, Ysmel Serrano, said shipping delays had affected deliveries, without going into details.
A fire at the country's largest refinery on Wednesday may also have played a part, though officials said operations were not affected.
Lawmaker Jose Guerra, an opponent of President Nicolas Maduro, alleged international suppliers were holding back because of unpaid debts from PDVSA.
"There are 15 ships (with Venezuelan-bound fuel imports) anchored in the Caribbean awaiting payment," Guerra told a press conference.
- Secretly importing gas? -
Guerra said the government was secretly importing 45,000 barrels of gasoline a day to hide the fact that domestic supply was insufficient to cover demand.
Venezuela is home to the world's largest oil reserves. But it mainly pumps an extra-heavy grade of oil that has to be mixed with lighter crude -- imported from abroad in recent years -- in order to be refined.
Maduro and his late predecessor Hugo Chavez -- who have used the country's oil wealth to fund lavish social programs -- have made cheap, abundant gasoline supplies a point of national pride.
Venezuela has the world's cheapest gas: one bolivar per liter, or 14 US cents at the country's highest official exchange rate.
At the black-market exchange rate, $1 buys 2,900 liters (766 gallons) of gasoline.
Venezuela has skidded to the brink of economic collapse as low oil prices have laid bare its overwhelming dependence on its chief export.
The country has been hit by devastating shortages of food, medicine and basic goods like deodorant and toilet paper.
Maduro, who is fighting efforts to force him from power, blames the crisis on an "economic war" by US-backed business interests.
His opponents blame the failure of 18 years of socialist "revolution" under Chavez and Maduro, who was elected to succeed his mentor in 2013.
Maduro's popularity has plummeted amid a crushing three-year recession and soaring inflation that the International Monetary Fund forecasts will hit 1,660 percent this year.