|Authorities are investigating a claim of responsibility allegedly made by the armed group, Harkat-ul-Jihad Islami [AFP]
Five people, including the owner of an internet cafe, have been detained for questioning over an email allegedly claiming responsibility for Wednesday's deadly blast in New Delhi that left 12 dead, police say.
Senior police officials told the Reuters news agency on Thursday that they had detained the owner of an internet cafe in the Kishtwar region of Indian-administered Kashmir from where they suspect the email was sent on Wednesday.
The blast inquiry was quickly turned over to the National Investigation Agency [NIA], established after the Mumbai attack of 2008 to investigate and prevent terror attacks.
Police were scouring the city for possible suspects, searching hotels, bus stands, railway stations and the airport, UK Bansal, a senior security official, said.
All roads out of the city were under surveillance as well, he said.
Of the dozens injured in the blast, 19 still remain in intensive care unit. An official said on Thursday the government would do all it can to provide medical assistance.
Late on Wednesday, police also released two sketches they said were based on descriptions given by witnesses who claimed they had seen someone with a briefcase waiting in line outside the building.
Authorities are investigating the claim of responsibility allegedly made by the armed group Harkat-ul-Jihad Islami [HUJI], an al-Qaeda-linked with bases in Pakistan and Bangladesh.
It has claimed responsibility for attacks in India in the past.
"That mail has to be looked at very seriously because HUJI is a very prominent terrorist group among whose targets India is one," SC Sinha, the NIA chief, said.
In an email to the NIA, the group called on India to repeal the death sentence of a man convicted in connection with an attack on the Indian parliament in 2001 who was awaiting execution by hanging.
"We are determined to track down the perpetrators of this horrific crime and bring them to justice,'' P Chidambaram, India's interior minister, told parliament on Wednesday.
Manmohan Singh, the Indian prime minister, conceded that there were "weaknesses in our security system and terrorists are taking advantage of them".
"We will never succumb to the pressure of terrorism," he said. "This is a long war in which all political parties, all the the people of India, have to stand united so that this scourge of terrorism is crushed."
|Delhi police have released a photofit of two suspects linked to Wednesday's deadly blast in the city [EPA]
However, Arun Jaitley, an opposition politician, asked in parliament: "Have we become so vulnerable that terrorist groups can almost strike at will?"
The attack was carried out even though Delhi had been on high alert because parliament was in session.
The blast erupted near a large crowd of people waiting in line to reach a reception counter where passes are made for entry to the court building, RK Singh, India's home secretary, said.
The blast will renew concern about the authorities' ability to prevent attacks, particularly in sensitive, high-risk areas.
"This is a glaring example of the shortage of intelligence, both human and technical," Ajai Sahni, executive director at the Institute for Conflict Management in New Delhi, said.
In May, a low-intensity blast outside the same Delhi court triggered panic but injured no one.
The explosion on Wednesday was outside the busiest gate of the building.
It was the first major attack in India since a string of bombs exploded in three busy Mumbai neighbourhoods on July 13, killing 24 people.