India's anti-corruption crusader Anna Hazare's arrest ahead of his fast against a proposed new anti-corruption law has triggered off countrywide protests.

Mr Hazare spent a night in Tihar jail in the capital, Delhi, despite a government decision to free him. His aides say he will leave the prison only after he is given permission to continue his fast at a city park.

Indian yoga guru Swami Baba Ramdev joined the crowds gathering to support Mr Hazare outside the prison.

Mr Hazare's protest has touched a chord among Indians, cutting across age. He has presented an increasing challenge to the Indian government over corruption in Asia's third largest economy, where a series of recent high-profile scandals have tarnished the government's image.

A large number of Mr Hazare's supporters belong to India's thriving, upwardly mobile middle class. They are using social media actively to organise protests in cities like Delhi and Mumbai.

As news of Mr Hazare's arrest spread, his supporters came out on the streets of many Indian cities to protest.

Mr Hazare's supporters say his detention proves that the government is "dictatorial and not heeding to the democratic rights of the people".

In the southern city of Hyderabad, activists from the Communist Party of India (CPI) burned an effigy representing the United Progressive Alliance (UPA) government.