The death of a young woman in the custody of the morality police has infuriated Iranians who have taken to the streets to protest in at least 50 cities and towns nationwide, with police using force to disperse demonstrations.
Here is a chronology of unrest in Iran, where security forces have staged tough crackdowns to stamp out dissent in the past.
July 1999 - Students angered by a police crackdown demonstrate in several Iranian cities, chanting anti-government slogans.
June 2009 - Hundreds of thousands of people protesting against the disputed re-election of President Mahmoud Ahmadinejad clash with police. The opposition says more than 70 people are killed. Officials say the death toll was half that. Thousands, including senior reformers, are detained and several are executed.
December 2009 - Influential dissident cleric Grand Ayatollah Hossein Ali Montazeri dies, prompting renewed demonstrations. Several people are killed in Tehran and other cities when thousands take to streets. State television put the death toll at eight.
July 2010 - A strike by merchants in Tehran’s influential Grand Bazaar forces the government to suspend plans to raise business taxes.
February 2011 - Two people are killed and dozens arrested as thousands of opposition activists take part in a banned rally in support of popular uprisings in Egypt and Tunisia.
March 2011 - Security forces fire teargas and clash with thousands of anti-government protesters demonstrating in Tehran and other cities against the treatment of opposition leaders, pro-reform websites report.
May 2011 - Iranian police expel a group of soccer fans who were chanting anti-Saudi slogans during an Asian Champions League match, Press TV reports. Tensions have mounted between the two since Saudi Arabia sent troops to help Bahrain quell protests inspired by the Arab revolts.
June 2011 - Iranian opposition website Sahamnews says security forces attack pro-reform demonstrators gathering in Tehran to mark the anniversary of the disputed 2009 election.
November 2011 - Iranians storm the British embassy in Tehran, smashing windows and burning the British flag to protest sanctions imposed by Britain on Iran. Britain closes the embassy and all diplomatic staff leave the country.
October 2012 - Police fire tear gas at protesters angered by the plunge in the value of the Iranian rial.
December 2017 - Iranian protesters angry over economic hardships and alleged corruption attacked police stations as security forces struggle to contain a strong challenge to the clerical leadership.
January 2018 - Iran warns of a tough crackdown against tens of thousands of demonstrators posing one of the boldest challenges to its clerical leaders since nationwide unrest shook the Islamist theocracy in 2009.
They began in Iran’s second city of Mashhad in the northeast and spread to Tehran and other urban centres. Iranians vented their anger over a sharp increase in prices of basic items like eggs, and a government proposal to increase fuel prices
November 2019 - Iran says 200,000 people took part in what may have been the biggest anti-government protests in the 40-year history of the Islamic Republic.
Supreme Leader Ayatollah Ali Khamenei described the two weeks of violence sparked by fuel price hikes as the work of a “very dangerous conspiracy.” Reuters reports 1,500 were killed by security forces.
January 2020 - Iran’s semi-official Fars news agency, in a rare report on anti-government unrest, said protesters in Tehran chanted slogans against the nation’s top authorities, after the powerful Revolutionary Guards admitted shooting down a passenger plane.
The report said the demonstrators on the street also ripped up pictures of Qassem Soleimani, the prominent commander of the Guard’s Quds Force who was killed in a U.S. drone strike.
May 2022 - Iranian protesters chanting anti-government slogans took to the streets of several cities including southwestern Abadan where a building collapse blamed on widespread corruption killed at least 24 people.
September 2022 - Iran's powerful Revolutionary Guards call on the Islamic Republic's judiciary to prosecute "those who spread false news and rumours" about Mahsa Amini, the woman whose death in police custody triggered protests.
The protests over Amini's death are the biggest in the Islamic Republic since 2019.
(Writing by Michael Georgy; Editing by Josie Kao)
