A bomb outside the Indian High Court in the capital Delhi has killed 11 people and injured at least 61.
Prime Minister Manmohan Singh called it a "cowardly act of a terrorist nature".
The bomb was apparently placed in a case near the first security checkpoint at the court, where people were queuing for passes, officials said. Investigators said they were taking seriously an email claim by the extremist group Harkat-ul Jihad al-Islami (Huji) that it planted the bomb.
The US state department says Huji is a terrorist organization with links to al-Qaeda. The group has been accused of carrying out attacks in India, Pakistan and Bangladesh. The leader of Huji, Ilyas Kashmiri, was reportedly killed in a US drone strike in north-western Pakistan in June.
Anchor Marco Werman speaks with the BBC's Mark Dummett who was on the scene.