The army was called in to control the violence in Kolkata after mobs attacked the police and torched vehicles during a three-hour shutdown by the All India Minority Forum to protest against the Nandigram turmoil. The forum also demanded the expulsion of controversial Bangladeshi writer Taslima Nasreen.

Kolkata Commissioner of Police Gautam Mohan Chakraborty said a curfew will be imposed in violence-hit areas of central Kolkata from 10 pm to 6 am.

Sources in the army headquarters in Kolkata said that two columns of the army staged a flag march in areas which witnessed violence.

Emerging from a high-level meeting with Chief Minister Buddhadeb Bhattacharya, West Bengal Home secretary P R Roy said that the government had asked for six columns of army to be deployed in the city.

Roy said that the army would work in tandem with the state police and stage flag marches in areas in central Kolkata.

The police said that the Forum activists attacked the police with brickbats and bottles. The police burst tear gas shells and used lathicharge to chase away the attackers in various areas of the city.

Even after the three-hour shutdown, more people joined in and continued to attack the police in which Deputy Commissioner (South) Javed Shamim was injured.

The shutdown was called to protest against the Nandigram violence and to press the demand for the cancellation of Taslima Nasreen's visa.

The home secretary said that the government was contemplating imposing curfew in the violence-hit areas at night.

Rapid Action Force personnel went into action after the police failed to control the mob, hundreds of whom pelted stones and empty glass bottles from lanes and bylanes leading to the main roads.

The attackers, Roy said, torched two offices of the CPI-M. Sixty people have been arrested, he said.

The home secretary said that after the Forum's programme was over, some 'unorganised' people joined and targeted the police.

The situation, he said, continues to be tense.

The violence totally crippled large parts of central Kolkata. Office-goers had a tough time and students in a number of schools in the affected region could not come out till late afternoon.

The affected areas were Padmapukur, Ripon Street, AJC Bose Road, Beniapukur, Park Circus besides parts of E M Bypass and central Kolkata, he said.