Delhi bomb: Indian group 'may be behind' court attack
India's Home Minister P Chidambaram has said it is likely that an attack on the Delhi high court was carried out by militants based in India.
"We can no longer point to cross-border terrorism as a source of terror attacks in India," Mr Chidambaram told the BBC.
He said the authorities were still trying to verify emails allegedly sent by two groups claiming responsibility for Wednesday's attack.
The death toll from the blast has now risen to 13, with 76 others wounded.
The two groups who have purportedly said they carried out the attack are Harkat-ul Jihad al-Islami (Huji), which has Pakistani origins and is accused of links to al-Qaeda, and the Indian Mujahideen.
The email reportedly sent by Huji was traced to a cyber cafe in Indian-administered Kashmir and police there have detained five people.
Mr Chidambaram said that even though Huji had claimed responsibility for the blast, the group had not been active in India for a while.
"There have been three major attacks in India recently - in Pune, Mumbai (Bombay) and Delhi.
"In respect of the Mumbai and Pune attacks, we are fairly certain they were carried out by Indian modules or India-based modules," Mr Chidambaram said, in his first media interview since the court bombing.
In the past, India has often blamed Pakistan-based groups for carrying out attacks on Indian soil.
"That threat remains - but we must also look at Indian modules or India-based modules which are capable of carrying out terror attacks," he said.
Mr Chidambaram said India would now have to focus on improving its counter-terrorism abilities and go after militant groups based in India.
He said the country's proximity to Pakistan and Afghanistan was a cause for worry and India was concerned about how to prevent the radicalisation of its youth.
The Indian government is under increasing pressure following the latest attack, with concerns that its security and intelligence agencies are still not in a position to handle the growing threat despite pledges to do so following the attacks on Mumbai in 2008.
"The government can build capacity and extend the intelligence network, but policing is a very complex task and there will be cases where the terrorist is able to slip through the cracks," Mr Chidambaram said.
Later, he told a news conference that those being questioned in Indian-administered Kashmir included the person suspected of sending the "Huji email".
He described the leads as "promising but not conclusive", and added that the likelihood of more attacks was high as India was in a troubled neighbourhood.