A little-known Muslim group has claimed responsibility for a set of coordinated bomb blasts that tore through a packed shopping area in the western Indian tourist city of Jaipur earlier this week.

An email to local media, from a group calling itself the Indian Mujahideen, declared open war on India and threatened more attacks on tourists.

"From the tourism point of view, this attack is to warn the entire crusaders of the world, US and Britain in particular, we Muslims are one across the globe and you won't find it easy in India as well," the email was quoted as saying by Reuters.

"Don't send your people to India and if you do so then you people will be welcomed by our suicide attackers," it said.

Eight bombs, some of which were strapped to bicycles, killed 61 people and injured 216 people when they exploded on Tuesday evening.

Police say they are still verifying the claim, and say the attack also bore some hallmarks of a Bangladeshi militant group, Harkat-ul-Jihad al Islami.

They have released a sketch of a man in his mid-20s who was heard speaking Bengali - the main language of Bangladesh - near the scene of one of the bomb blasts.

They also say they have traced the email to a cybercafe in the town of Sahibabad, just outside the capital New Delhi, and taken the owner and his son in for questioning.

Observers say it is unusual for any group to claim responsibility for a bomb attack in India.

Islamist militant groups in Pakistan and Bangladesh intent on fuelling tensions between Muslims and Hindus in India, and undermining the fragile India-Pakistan peace process, are often blamed for such attacks.

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