A crackdown by New Delhi on the country’s burgeoning anti-corruption movement on Tuesday sparked protests across India after its leader was jailed for refusing to cancel a hunger strike promoting tougher anti-graft legislation.

The arrest in the capital of Anna Hazare, a veteran social activist, marks an escalation in a tense stand off between prime minister Manmohan Singh and civil society campaigners, suspected by the ruling Congress party to be extremist agitators. The confrontation comes at a time when Sonia Gandhi, the party’s president, is outside the country undergoing medical treatment.

By Tuesday evening, hundreds of demonstrators had taken to the streets in Delhi, Mumbai, Bangalore and Chennai demanding the release of Mr Hazare from Delhi’s Tihar jail and insisting that civil rights were under threat in the world’s largest democracy.