Police found an unexploded bomb in the western Indian city of Surat, one of the world's biggest diamond-polishing centres, on Tuesday, three days after a series of bombs in the same state killed 45 people.

"We received a phone call from a residence in Surat informing us about a suspicious package. A bomb squad was sent. They are now defusing it," said a senior police officer, who asked not to be named.

A series of 16 bombs ripped through the nearby city of Ahmedabad in the state of Gujarat on Saturday, a day after bombs killed one woman in the IT hub of Bangalore.

A group called the "Indian Mujahideen" said it carried out the Ahmedabad attack, writing in an e-mail sent five minutes before the first blast that it was in revenge for a 2002 massacre in Gujarat of around 2,500 people, mainly Muslims, by Hindu mobs. On Sunday, two unexploded car bombs were also found by police in Surat.