India's anti-corruption campaigner Anna Hazare has spent a night in jail in Delhi, despite being freed by the government after being arrested for planning a hunger strike.
The arrest of Anna Hazare early on Tuesday sparked spontaneous protests in cities across the country.
A close aide, who had also been arrested, said Hazare was refusing to leave the jail until he obtained government permission to continue his fast in a park in the capital.
Police also released about 1,500 of Hazare's followers detained in Delhi for defying the police order not to protest.
Hazare, 74, was taken into custody as he prepared to lead a parade to a public park in New Delhi where he was to begin a "fast unto death".
In a pre-taped appeal, Hazare urged his supporters to protest despite his arrest.
"My dear countrymen, the second freedom struggle has begun, and now I have also been arrested. But will this movement be stopped by my arrest? No, not at all. Don't let it happen," he said.
Many of the detainees arrested in New Delhi were driven to a sports stadium in northern New Delhi where a large crowed gathered outside in a tense stand-off with police, AFP reported.
Police on Monday denied Hazare permission to fast near a cricket stadium because he failed to meet certain conditions, including ending his fast in three days and ensuring not more than 5,000 people took part.
The Indian Prime Minister Manmohan Singh has criticised the hunger strike campaign by Hazare as "totally misconceived" and deliberately confrontational.
"The path he has chosen is totally misconceived," Singh said in an address to parliament that was repeatedly interrupted by cries of "shame" from the opposition benches.
High profile campaign
Hazare ended a four-day hunger strike in April after the government set up a committee to draft legislation to create an anti-corruption ombudsman. The committee included Hazare and other non-elected
The legislation was introduced in India's parliament earlier this month but Hazare demanded that it be made tougher to include the prime minister and the judiciary in its remit. The current draft of the law does not include them.
Hazare's protest has tapped into deep public anger against corruption in India as the Congress party-led government battles a series of graft scandals.
These include the sale of mobile phone licenses and the hosting of last year's Commonwealth Games, which together lost the country as much as $40bn, according to government auditors.
The Indian parliament has been paralysed by anti-corruption protests for two weeks, stalling crucial legislation.