JEDDAH: The regime in Tehran is braced for Iran’s biggest protests in three years on Friday amid mounting anger over the death of a young Kurdish woman in police custody.

Activist groups say Mahsa Amini, 22, was beaten to death after being arrested by the country’s morality police for wearing a hijab in an “improper way’.

At least 31 people have been killed in a security crackdown on protests that began in Kurdistan province and spread to at least 13 cities, including the capital. Iranians had rallied “to achieve their fundamental rights and human dignity. .. and the government is responding to their peaceful protest with bullets,” Iran Human Rights director Mahmood Amiry-Moghaddam said.

There has been widespread global condemnation of the crackdown on protesters, and on Thursday the US government imposed sanctions on the morality police and leaders of other Iranian security agencies, who “routinely employ violence to suppress peaceful protesters.”

Iranian authorities again throttled and blocked mobile internet access on Thursday, to prevent Iranians from hearing news of protests or planning new ones. “People in Iran are being cut off from online apps and services,” Instagram chief Adam Mosseri said.

WhatsApp said it was “working to keep our Iranian friends connected and will do anything within our technical capacity to keep our service up and running.”

At the UN in New York, Iranian President Ebrahim Raisi backed out of an interview with CNN journalist Christiane Amanpour at which he was expected to be grilled over the protests. Amanpour said the president had demanded that she wear a headscarf, she refused, and he failed to turn up for the interview.