Amnesty International says dozens of women are at risk of "long jail terms" for protesting against the compulsory hijab in Iran.

Iranian authorities have arrested dozens of women who have protested against the hijab by removing their head scarves in public.

In an official statement on February 23, Iranian police warned that women who protested the law would now be charged with "inciting corruption and prostitution," which carries a maximum sentence of 10 years in prison.

London-based Amnesty International said in a statement on February 26 that the move "has put dozens at immediate risk of unjust imprisonment and represents an alarming escalation of the authorities' violent crackdown on women's rights."

Amnesty said more than 35 women had been "violently attacked and arrested" in the capital, Tehran, alone since December 2017 for taking part in "ongoing peaceful protests."

"This is a deeply retrograde move by the Iranian authorities in their ongoing persecution of women who dare to speak out against compulsory veiling. It places many women at serious and immediate risk of unjust imprisonment while sending a chilling message to others to keep quiet while their rights are being violated," said Magdalena Mughrabi, Amnesty's deputy director for the Middle East and North Africa.

Last week, the authorities arrested two more women who protested against the hijab in Tehran.

Shaparak Shadizadeh, one of the two women arrested, was taken into custody on February 21. Her family says she was beaten up during the arrest.

Another woman was reportedly arrested on February 22.

A video shows a police officer kicking her down from a utility box where she had staged her peaceful protest.

Women's dress has been heavily scrutinized in the Islamic republic since the 1979 revolution, when adherence to an Islamic dress code became compulsory.

The dress code dictates that women's hair and body must be covered in public.

Morality police launch regular crackdowns on those who do not fully respect rules relating to the hijab.