Protesters in Iran marched through the streets of multiple cities overnight in the most widespread demonstration in weeks amid the monthslong unrest that’s gripped the Islamic Republic, online videos purported to show Friday.

The demonstrations, marking 40 days since Iran executed two men on charges related to the protests, show the continuing anger in the country. The protests, which began over the Sept. 16 death of 22-year-old Mahsa Amini after her arrest by the country’s morality police, have morphed into one of the most serious challenges to Iran’s theocracy since the 1979 Islamic Revolution.

Videos showed demonstrations in Iran’s capital, Tehran, as well as in the cities of Arak, Isfahan, Izeh in Khuzestan province and Karaj, the group Human Rights Activists in Iran said. The Associated Press could not immediately verify the videos, many of which had been blurred or showed grainy nighttime scenes.

In Iran’s western Kurdish regions, online videos shared by the Hengaw Organization for Human Rights showed burning roadblocks in Sanandaj, which has seen repeated demonstrations since Amini’s death.

Hengaw shared one video that included digitally altered voices shouting: “Death to the Dictator!” That call has been repeatedly heard in the demonstrations, targeting Iran’s 83-year-old Supreme Leader Ayatollah Ali Khamenei. Other videos purportedly shot in Tehran had similar chants, as well as scenes of heavily protected riot police in the street.

Protesters also marched in Iran’s Sistan and Baluchestan province near Pakistan after Friday prayers, online videos showed. Anti-government demonstrations have been happening for months as well on Fridays in the restive province, which is a majority Sunni region. Its Baluch people long have complained about being treated as second-class citizens by Iran’s Shiite rulers.

Iranian state media did not immediately acknowledge the demonstrations.

Over 500 Killed in Demonstrations

Since they began, at least 529 people have been killed in demonstrations, according to Human Rights Activists in Iran. Over 19,700 others have been detained by authorities amid a violent crackdown trying to suppress the dissent. Iran for months has not offered any overall casualty figures, though the government seemed to acknowledge making “tens of thousands” arrests earlier this month.

The demonstrations had appeared to slow in recent weeks, in part due to the executions and crackdown, though protest cries could still be heard at night in some cities.

Forty-day commemorations for the dead are common in Iran and the wider Middle East. But they also can turn into cyclical confrontations between an increasingly disillusioned public and security forces that turn to greater violence to suppress them, as they had in the chaos leading up to Iran’s 1979 revolution.

Iran’s hard-line government has alleged without offering evidence that the demonstrations are a foreign plot, rather than homegrown anger.

The country’s rial currency has collapsed to new lows against the U.S. dollar. Tehran continues to enrich uranium closer than ever to weapons-grade levels after the collapse of its nuclear deal with world powers and has enough of a stockpile to build “several” atomic bombs if it chooses. Meanwhile, Tehran has been arming Russia with the bomb-carrying drones Moscow has been using in the war in Ukraine.