Russia has been criticised for letting Chechen authorities impose a compulsory Islamic dress code for women.
A report by Human Rights Watch includes testimonies from dozens of Chechen women who were threatened or even attacked with paintballs by young men enforcing the 'virtue campaign'.
The rights group says some attacks involved Chechen security forces.
The campaign has the backing of President Ramzan Kadyrov, relied on by Moscow to stabilise the region.
In 2007, President Kadyrov issued an edict that banned bareheaded women from entering state buildings. Though this is in direct violation of Russian law, it is strictly followed today.
Since then, an unofficial campaign limiting Chechen women's freedoms has been gaining strength, Human Rights Watch says.
A Russian rights activist, Natalya Estemirova, who had publicly criticised the Islamic dress campaign, was abducted from Grozny in July 2009 and her body was later found in the neighbouring republic of Ingushetia.
Bruised and scared
In June 2010, dozens of women were targeted in paintball attacks for not donning headscarves or because their skirts or sleeves were not long enough.
One woman interviewed for the report described her terror as she thought a real gun was being aimed at her. She said the incident left her bruised and scared ever to leave the house without a headscarf again.
President Kadyrov praised the paintball attackers, and leaflets later surfaced warning that women who failed to wear headscarves could face "more persuasive measures".
"The enforcement of a compulsory Islamic dress code on women in Chechnya violates their rights to private life, personal autonomy, freedom of expression, and freedom of religion, thought, and conscience," the HRW report says. "It is also a form of gender-based discrimination prohibited under international treaties to which Russia is a party."
"These attacks against women are outrageous, and the alleged involvement of law enforcement officials is of special concern," HRW's Russia researcher Tanya Lokshina says. "The Kremlin should publicly and unambiguously make clear... that Chechen women, like Russian women, are free to dress as they choose."
Chechnya was devastated by two separatist wars following the collapse of the Soviet Union in 1991.
34-year-old Mr Kadyrov has been credited with bringing some stability to the region but he has come under heavy criticism from international rights groups over alleged human rights abuses.