At least 16 people have been killed during a week of unrest in Iran, Reuters reported, citing rights groups.
Protests against rising inflation have swept across the country, sparking violent clashes between demonstrators and security forces.
Deaths and arrests have been reported by both state media and rights groups over the week, although figures vary.
The protests are the largest in three years and, while smaller than some previous unrest that has rocked the Islamic republic, they come at a time of vulnerability when the economy is in shambles and international pressure is mounting.
US President Donald Trump has threatened to come to the aid of protesters if they turn violent, saying on Friday "we are prepared to act", but without specifying what moves he was considering.
The warning prompted threats of retaliation against US forces in the region from senior Iranian officials, with Supreme Leader Ayatollah Ali Khamenei saying Iran "will not yield to the enemy".
The Kurdish rights group Hengaw said at least 17 people had been killed since the protests began. HRANA, a network of human rights activists, said at least 16 people had died and 582 had been arrested.
Iran's police chief Ahmad-Reza Radan said security forces had been targeting protest leaders over the past two days, noting that "a large number of leaders in cyberspace have been detained."
The most intense clashes were recorded in western Iran, but there were also protests and clashes between demonstrators and police in the capital Tehran, in central regions and in the southern province of Baluchistan.
Late yesterday, the governor of Qom, the conservative center of Iran's Shiite Muslim clerical elite, said two people had been killed there in the unrest, adding that one of them died when an explosive device he had made detonated prematurely.