India anti-corruption activist Anna Hazare detained
Police in India have detained prominent activist Anna Hazare hours before he had planned to start a fast against a proposed new anti-corruption law.
As news of the arrest spread, his supporters came out on the streets of many Indian cities in protest.
Mr Hazare had pledged to go on hunger strike in the capital, Delhi, Tuesday despite police denying him permission to fast for more than three days.
A minister says the fast is acceptable, but only within the limits of the law.
India's Home Minister P Chidambaram told reporters: "This government is not against democratic and peaceful protest. But that right must be exercised subject to conditions laid down by authorities charged with the duty of keeping law and order and public peace."
Mr Chidambaram added some 1,300 people had been detained at different places in Delhi, with most of them being taken to a stadium in the city.
Plainclothes police officers picked up Anna Hazare from a house in Delhi and drove him away in an unmarked car, fellow activist Akhil Gogoi told the AFP news agency.
It is understood that Mr Hazare, 74, is being held in a government facility. His supporters plan to appeal to the Supreme Court against his detention.
India's Home Secretary RK Singh said Mr Hazare had been detained because he said he "intended to defy prohibitory orders" and go on fast at a park in Delhi.
The police laid down six conditions for the fast to take place, which included the following: the fast should be limited to three days; no more than 400 to 500 people are allowed to gather, and there is parking for a certain number of vehicles.
Mr Hazare has called the proposed legislation a "cruel joke" and has described the fight against corruption as the "second war of Independence". He said the movement would not stop with his arrest.
In a recorded video message on YouTube, he said: "Millions have joined the movement against corruption. The battle will continue, and more people will court arrest. There will come a time when there will be no space in India's jails."
Lawyer Prashant Bhushan, a prominent supporter of Mr Hazare, said his detention proved that the government is "dictatorial and not heeding to the democratic rights of the people".
Several other prominent supporters of Mr Hazare were also detained.
Finance Minister Pranab Mukherjee said "nobody was stifling the voice of protest" by detaining Mr Hazare.
"It is the legitimate right of every individual to protest, but at the same time there are certain rules and laws. If the police believe that [a protest] can lead to a law and order problem, then it can impose certain conditions," he said.
On Monday, Indian Prime Minister Manmohan Singh said hunger strikes by campaigners would not help to tackle corruption.
Mr Hazare says the proposed anti-corruption ombudsman should be able to investigate any official - including the prime minister and judges.
India has recently been hit by a string of high-profile corruption scandals, including a multibillion dollar alleged telecoms scam, alleged financial malpractices in connection with the Delhi 2010 Commonwealth Games and allegations that houses for war widows were diverted to civil servants.
Critics of the government say the scandals point to a pervasive culture of corruption in Mr Singh's administration.
A recent survey said corruption in India cost billions of dollars and threatened to derail growth.