Police fired tear gas shells and resorted to lathicharge Saturday to disperse thousands of people who had gathered at Raisina Hill here to protest against the gang-rape of a 23-year-old woman in a bus six days ago.
But the government said it was already acting on the protesters' demands and appealed for calm.
Some of the protesters, who were injured in the police action, were taken to a hospital.
Police first used water canons to disperse the crowd but as the protesters did not budge, they used tear gas shells and wielded sticks.
Policemen were seen chasing people, many of them students. Some protesters resorted to stone-pelting too.
As the people reassembled, police again used water cannons to disperse them.
Apart from Raisina Hill, protesters had converged at India Gate too.
Minister of State for Home R.P.N. Singh said police had been asked to exercise maximum restraint and the government was acting on people's demands.
The minister told a news channel that police could not allow people to break barricades and enter government buildings.
Calling for calm, he said there was no police action at places where protesters were peaceful.
Some people, he said, were trying to make it an unruly mob.
"I'm not justifying use of tear gas," R.P.N. Singh said but added that there were attempts to break barricades in the sensitive area close to the president's house and other key government offices.
"Government is hearing them (the protesters) loud and clear," he said.
Police would seek maximum punishment for the guilty in the gang-rape case and strict steps were being taken to ensure safety of women, he added.
Police have arrested all the six accused in the case.
The rape victim is currently battling for her life in a hospital here.
R.P.N. Singh said the government was willing to talk to the people but the protest should be orderly.
But the protesters, which included school students, lambasted police action and said they would stay put.
"We were protesting in a peaceful manner. They started beating us. Is this democracy? We are just demanding a strong law," Ritika, a college student, said.
"We are not afraid of police action. We'll come here daily till we get justice," said Ruchi, another student.
"Why tear gas shells; why lathicharge; why water cannons? We are students, not terrorists. Why so much police here; why don't they stand on the road to stop crime?" she added.
Protestors were carrying posters and banners.
"My tight top, high heels are not an invitation," read one poster.
Another read: "Law of zero tolerance for rapists."
The protesters started arriving at India Gate since early morning and were joined by former army chief Gen. V.K. Singh.
They then began marching towards the high-security Rashtrapati Bhavan on Raisina Hill but were stopped by security personnel, who had put up barricades.
Outrage has been swelling across the country after the woman was tortured and subjected to brutal gang-rape in a moving private bus Dec 16 in Delhi while she and a male friend were going home after watching a film.