Street protests over water shortages in south-west Iran continued for a sixth night on Tuesday.
At least two young men have been shot dead in the demonstrations in Khuzestan, and residents of Tehran and other cities are protesting in solidarity.
Officials blame armed protesters for the deaths, but activists said the men were killed by the security forces.
At least 31 demonstrations, including rallies by workers and farmers, were held in Iran on Monday and Tuesday, the dissident Human Rights Activists News Agency said.
Campaigners and local monitoring groups said the government cut the internet in Khuzestan to block videos of the growing unrest.
Footage filmed overnight in the city of Izeh showed protesters shouting slogans including “death to the principle of Velayat-e Faqi” and “we don’t want Islamic Republic”.
Velayat-e Faqi is the underlying ideology in Iran that permits the clergy to rule over the state.
Other videos uploaded to social media showed the security forces using tear gas to disperse protesters. The semi-official news agency Fars said “rioters” shot one policeman dead and injured another in the port city of Bandar Mahshahr.
Since the protests began on July 15, they have grown in size and in violence as frustration among residents rises. In the Khuzestan city of Susangerd, a decommissioned Iraqi tank serving as a monument to the 1980-88 Iran-Iraq war was set on fire.
Iran is facing its worst drought in 50 years and is experiencing power cuts as a result. The water shortage is also affecting households and agriculture.
According to the Iranian Department of Water and Sewerage, at least 110 cities have struggled with regular water cuts since the start of the summer. Iran ranks fourth in the world for water scarcity, meaning it does not have enough water for consumption.
In June, Iran’s energy minister, Reza Ardakanian, said 2021 was “one of the driest years in five decades”.
An official at the country’s meteorological organisation put it more simply: “Bluntly speaking, there is no water.” The official, from the organisation’'s centre for drought, said there had been a 50 to 85 per cent reduction in precipitation this year, particularly in the southern and eastern regions, which include Khuzestan.
The Zayandeh Rud river in Isfahan has long been a victim of water extraction, often running dry, as has Lake Urmia, once the second-largest salt lake in the world.
Khuzestan, however, used to include large wetlands and marshes. While almost a third of Iran’s rivers once flowed through the region, it is now a wasteland owing to droughts, dam construction, mismanagement and oil extraction.
A controversial dam built in 2018 on the Karun river, one of Khuzestan’s vital resources, reduced the water supply by two thirds. Shortages have been a problem for nearly 40 years, often leading to protests and clashes.
Experts have repeatedly issued warnings that water scarcity will eventually lead to a larger conflict within the region.
Iran’s economy is also struggling, largely because of sanctions imposed on its oil industry by former US president Donald Trump. The pandemic has worsened the problem.
Workers, including thousands in the energy sector, have protested for months. Discontent is growing over mismanagement, high unemployment and an inflation rate above 50 per cent.