A man has been killed during a second night of protests over severe water shortages in south-west Iran, state media reports.
An official in Khuzestan province said the protester was accidentally hit by people who were firing in the air, according to state news agency IRNA.
Opposition sources accused the security forces of causing the death.
Iran is facing a severe drought, and there is growing public anger over water and power shortages.
The death happened in the town of Shadegan, and pictures of the man have been shared widely across social media.
"In this gathering, the rioters started shooting in the air to provoke people and, unfortunately, one of the bullets hit a person present there, killing him," Acting Governor Omid Sabripour told IRNA.
The man has been identified as a member of the ethnic Arab minority that is based in Khuzestan, located on the border with Iraq. Opposition media based outside the country say he was killed by the security forces, with reports that they opened fire on the demonstrations.
Iranian authorities have downplayed the scale of the protests, which have been held in several of the oil-rich province's towns and cities.