The group of 11 men were sentenced to life for gang-raping a pregnant woman in 2002 during religious turmoil in the state of Gujarat.
A decision to free almost a dozen men from prison for "good behaviour" after they raped a pregnant woman has sparked outrage in India.
Women protested in the country's capital on Thursday against the move to end the men's life sentences after they had spent 14 years in jail.
The 11 men, said to be Hindu, were convicted in 2008 after they raped a Muslim woman during religious violence in 2002 in the country's western state of Gujarat.
On Thursday, activists in New Delhi held signs reading "Protecting rapists and penalising victims" as they directed their anger at the state government.
Local officials said the men were released in line with India's remission policy, which considers convicts' age and conduct while in prison.
"You are freeing murderers and rapists in this country, indirectly giving a signal to the gangsters of the country that they can go ahead and do what they want," said Mariam Dhawale, of the All India Democratic Women's Association.
The rape victim, now in her 40s, said in a statement that the decision to release her attackers' had "left her numb".
"How can justice for a woman end like this? I trusted the highest courts in our land," she said, adding that no authorities reached out to her before making the decision.
"Please undo this harm. Give me back my right to live without fear and in peace."
The region's top bureaucrat told Reuters the district jail advisory committee had recommended the men's release after considering the time they had spent in jail and their good behaviour.
"The fact is they had spent close to 15 years in jail and were eligible for remission," Sujal Jayantibhai Mayatra said.
Indian laws allow convicts to seek remission after 14 years in jail, officials said.