Iran's supreme leader Ayatollah Ali Khamenei has broken his silence on the protests gripping the country, blaming the US and Israel for what he described as "planned riots." Speaking at a military graduation ceremony in the capital on Monday, Mr Khamenei said the protests were planned and not staged by "ordinary Iranians". "I say clearly that these disturbances and insecurities were designed by America and the usurping and fake Zionist regime," he said in the speech. It is the first time he has addressed the protests which have swept across the country following the death of Kurdish woman Mahsa Amini while in police custody. Mr Khamenei said he was "heartbroken" by Amini's death, which sparked anti-regime demonstrations across all provinces. Protesters are using her death as an excuse to take to the streets, he added, saying they would have found another reason to demonstrate against the regime had she not died. He also also accused protesters of burning Qurans and attacking mosques. His comments come a day after a crackdown against university students in Tehran, with classes cancelled and students calling for a nationwide strike. Sharif University's Students' Association has called on institutions across the country to cease teaching after numerous students were arrested during <a href="https://www.thenationalnews.com/mena/iran/2022/10/03/iran-university-suspends-classes-as-mahsa-amini-protests-enter-third-week/" target="_blank">on-campus demonstrations</a> on Sunday night. Classes at the university have been cancelled. Iran's security forces, namely the Islamic Revolutionary Guard Corps' Basij force, have tried to quash the protests with violence. Human rights groups say more than 100 people have been killed since the protests began three weeks ago, and more than 1,500 have been arrested. The police "are obliged to stand up to criminals and ensure the safety of society", Mr Khamenei said, voicing support for the country's "wronged" security forces. Many protesters have demanded the supreme leader's departure in the biggest unrest Iran has seen since 2019. "Death to the dictator" has been a common chant at demonstrations, which began in Iran's Kurdistan province following Ms Amini's burial.