Protests erupted across Iran on Friday after the government imposed petrol rationing and raised its fuel prices. (Photo: ANI)

At least 36 people have died since protests erupted across over the fuel price hike.

Al Arabiya citing sources reported that the Iranian security forces fired tear gas to disperse protesters in Martyrs' square in Tehran.

On Sunday, Iran's Supreme leader Ayatollah Ali Khamenei backed the government's decision to hike fuel prices despite ongoing protests in the country.

"I am not an expert in this field, but I had asserted before that I would back whatever decision the heads of the three branches [legislative, judiciary, administrative] make," Khamenei said, Anadolu Agency reported citing Iranian media.

Protests erupted across Iran on Friday after the government imposed petrol rationing and raised its fuel prices.

According to officials, the new fuel policy, which has seen prices rise by at least 50 per cent, will free up money to help the poor.

Khamenei also called on the government to take every step possible to alleviate people's economic concerns. "Authorities should use all their capacities to minimize people's concerns over this [gas rationing] plan," he said.

Iran has been hit hard by the reimposition of US sanctions last year, after US President Donald Trump backed out of the 2015 nuclear deal with Tehran.