Sporadic protests erupted in cities across Iran, state news agency IRNA said on Saturday, a day after the government announced a surprise decision to ration petrol and hike its price.
The demonstrations on Friday night were "severe" in Sirjan in central Iran as "people attacked a fuel storage warehouse in the city and tried to set fire to it," the news agency reported.
But police intervened to prevent them.
IRNA said "scattered" protests also broke out in other cities including Mashhad, Birjand, Ahvaz, Gachsaran, Abadan, Khoramshahr, Mahshahr, Shiraz and Bandar Abbas.
They were mostly limited to blocking traffic and were over by midnight, it added.
Iran imposed petrol rationing and raised pump prices by at least 50 percent on Friday, saying the move was aimed at helping citizens in need with cash handouts.
The measure was expected to bring in 300 trillion rials ($2.55 billion) per annum, the head of the country's Planning and Budget Organisation, Mohammad Bagher Nobakht, said on state television.
About 60 million Iranians in need would get payments ranging from 550,000 rials ($4.68) for couples to slightly more than two million rials ($17.46) for families with five members or more, he added.
Under the scheme, drivers with fuel cards will pay 15,000 rials (13 US cents) a litre for the first 60 litres of petrol bought each month, with each additional litre costing them 30,000 rials.
Fuel cards were first introduced in 2007 with a view to reforming the subsidies system and curbing large-scale smuggling.
Iran's economy has been battered since May last year when President Donald Trump unilaterally withdrew the United States from a 2015 nuclear agreement and reimposed crippling sanctions.
The rial has plummeted in value against the US dollar, inflation is now running at more than 40 percent and the International Monetary Fund projects that the troubled economy will contract by nine percent this year and stagnate in 2020.
President Hassan Rouhani said on Saturday that currently "75 percent of the country are under preassure" and the extra revenue will only go to them, not the treasury.
Rouhani had tried to hike fuel prices in December but was blocked by parliament in the wake of protests that rocked Iran for days.
The speaker at the time ruled out the move as unpopular and said it was "not in the interests of the country".