At least four protesters were shot dead Saturday night in the Iranian city of Khorramshahr, 650 kilometers (400 miles) southwest of Tehran, videos shared on social media early Sunday seem to show.
The demonstration was reportedly over the scarcity of clean drinking water in the country's south. The footage also shows protesters chanting "Death to Khamenei" against Iran's supreme leader.
Video circulated by BBC's Persian service appeared to show automatic gunfire as people protested in the streets. People can also be seen fleeing after tear gas was fired.
According to one Twitter account, the protesters in Khorramshahr were also "attacking the regime's banks."
The state-run IRNA news agency reported that protesters threw stones and debris at police, who responded with tear gas. It did not mention the gunfire.
The protests Saturday night come after three days of demonstrations in Tehran, including protesters confronting police outside parliament and officers firing tear gas at the demonstrators. The rallies led to the temporary closure of the city's Grand Bazaar.
Unrest in the Islamic republic has been growing as international firms pull away in the wake of U.S. President Donald Trump's decision to withdraw from the 2015 nuclear deal and reimpose economic sanctions.
