A bomb outside the Indian High Court in the capital Delhi has killed 10 people and injured at least
Police said the bomb was apparently placed in a case near the first security checkpoint at the court, where people were queuing to get passes for the day's hearings.
The BBC's Mark Dummett visited the scene of the explosion and said questions would be asked about how such an incident could have happened despite tight security.
Investigators said they were taking seriously an email claim by the extremist group Harkat-ul Jihad al-Islami (Huji) that it planted the bomb.
"It would be very premature to make any comment on the mail at this stage, but yes, that mail has to be looked at seriously, because Huji is a very prominent terrorist group," SC Sinha, Director General of India's National Investigation Agency, told reporters.
The email reportedly demands that a man sentenced to death for involvement in an attack on Delhi's parliament ten years ago should not be hanged.
The US state department says Huji is a terrorist organisation with links to al-Qaeda. The group has been accused of carrying out attacks in India, Pakistan and Bangladesh.