Classes were suspended at Tehran's Sharif University on Monday, after clashes erupted between students and security forces amid protests over the death of Mahsa Amini in police custody.

"Sharif University of Technology announced that due to recent events and the need to protect students ... all classes will be held virtually from Monday," Iran's Mehr state news agency said.

What happened at the university?

Two hundred students gathered at the university campus and chanted protest slogans.

According to Mehr, students shouted "woman, life, liberty" and "students prefer death to humiliation."

Mehr reported security forces fired tear gas and paintballs at the students. The science minister later came to the university to speak with the students.

Germany, US both indicate further potential sanctions

Germany's Foreign Minister Annalena Baerbock condemned Tehran's use of "brute force" at the protest and called for sanctions in a tweet.

"The courage of Iranians is incredible… And the regime's brute force is an expression of sheer fear in the face of the power of education and freedom," Baerbock tweeted.

"It's hard to accept the fact that our foreign policy options are limited. But we can amplify their voice, raise awareness, denounce and sanction. And that's what we're doing."

US President Joe Biden said later on Monday that he remained "gravely concerned" about reports of an intensifying violent crackdown on protesters in Iran. 

"This week, the United States will be imposing further costs on perpetrators of violence against peaceful protesters. We will continue holding Iranian officials accountable and supporting the rights of Iranians to protest freely," Biden said in a statement. 

Ayatollah Khamenei breaks his silence on the protests

Iran's ultraconservative Supreme Leader Ayatollah Ali Khamenei threw his full support behind the security forces on Monday, accusing the protesters of "rioting."

He also said that the US and Israel were behind the protests rather than "ordinary Iranians."

He claimed to be "heartbroken" over the death of 22-year-old Mahsa Amini — the incident that initially sparked the nationwide protests — while also condemning the "insecurity" in the streets.

"This rioting was planned," he told a cadre of police students in Tehran. "These riots and insecurities were designed by America and the Zionist regime, and their employees."

Official warns of 'destabilizing' protests

Iran's parliamentary speaker, Bagher Qalibaf, urged protesters not to allow the demonstrations to become "destabilizing" for the country and promised to "amend the structures" of the country's morality police.

Qalibaf is a former influential commander in Iran's Revolutionary Guard.

"The important point of the [past,] protests was that they were reform-seeking and not aimed at overthrowing" the system, Qalibaf said, referring to protests by teachers and retirees over pay.

"I ask all who have any [reasons to] protest not to allow their protest to turn into destabilizing and toppling" of institutions.

"Creating chaos in the streets will weaken social integrity, jeopardizing the economy while increasing pressure and sanctions by the enemy,'' Qalibaf said, referring to sanctions imposed by Washington.

The lawmaker promised that Tehran would "amend the structures and methods of the morality police" in response to the protests.

ab, sdi, msh/kb (AFP, AP)