Protests in Iran entered a more violent phase on Sunday as students, who defied an ultimatum by the Revolutionary Guards and a warning from the president, were met with tear gas and gunfire from security forces, social media videos showed.
The confrontations at dozens of universities prompted the threat of a tougher crackdown in a seventh week of demonstrations sparked by the death of 22-year-old Mahsa Amini after she was arrested by the morality police for attire deemed inappropriate.
"Security is the red line of the Islamic Republic, and we will not allow the enemy to implement in any way its plans to undermine this valuable national asset," hardline President Ebrahim Raisi said, according to state media.
Iranians from all walks of life have taken to the streets since Amini's death in protests that the clerical rulers said were endangering the Islamic Republic's security.
Authorities have accused Islamic Iran's arch-enemies the United States and Israel and their local agents of being behind the unrest to destabilise the country.
What began as outrage over Amini's death on Sept. 16 has evolved into one of the toughest challenges to clerical rulers since the 1979 revolution, with some protesters calling for the death of Supreme Leader Ayatollah Ali Khamenei.
The top commander of Iran's Revolutionary Guards told protesters that Saturday would be their last day of taking to the streets, the harshest warning yet by Iranian authorities.
Nevertheless, videos on social media, unverifiable by Reuters, showed confrontations between students and riot police and Basij forces on Sunday at universities all over Iran.
One video showed a member of Basij forces firing a gun at close range at students protesting at a branch of Azad University in Tehran. Gunshots were also heard in a video shared by rights group HENGAW from protests at the University of Kurdistan in Sanandaj.
Videos from universities in some other cities also showed Basij forces opening fire at students.
Across the country, security forces tried to block students inside university buildings, firing tear gas and