A man fills up his car’s tank at a petrol station, after fuel price increased in Tehran, Iran November 15, 2019. Nazanin Tabatabaee/WANA (West Asia News Agency) via REUTERS

A cyberattack disrupted the sale of heavily subsidized gasoline in Iran on Tuesday, state media reported, causing long lines at gas stations across the country weeks before the anniversary of 2019 street protests that followed fuel price hikes.

Iran says it is on high alert for online assaults, which it has blamed in the past on the United States and Israel. The United States and other Western powers meanwhile have accused Iran of trying to disrupt and break into their networks.

“The disruption at the refueling system of gas stations… in the past few hours, was caused by a cyberattack,” state broadcaster IRIB said. “Technical experts are fixing the problem and soon the refueling process…will return to normal.”

The oil ministry said only sales with smart cards used for cheaper rationed gasoline were disrupted and clients could still buy fuel at higher rates, the ministry’s news agency SHANA reported.

The disruptions came ahead of the second anniversary of an increase in fuel prices in November 2019 which led to widespread street protests in which hundreds were reported to have been killed by security forces.

Videos posted on social media showed apparently-hacked street signs carrying messages such as “Khamenei, where is our gasoline?”, in a reference to Supreme Leader Ayatollah Ali Khamenei.

Reuters could not independently authenticate the videos but Iran’s semi-official Mehr news agency confirmed that some signs had been hacked.

In the past, Iran has been targeted by a series of cyberattacks such as one in July when the website of the transport ministry was taken down by what state media said was a “cyber disruption.”