NEW DELHI — An al Qaeda-linked terror group claimed responsibility for a briefcase bomb that killed at least 11 people and injured more than 65 others when it exploded Wednesday morning outside a New Delhi courthouse.
The Pakistan-based militant group Harkat-ul-Jihadi claimed responsibility for the deadly explosion in an email to Indian media demanding clemency for a terrorist on death row.
India's main opposition political party, the Hindu nationalist Bharatiya Janata Party, said the bombing could be linked to the approaching anniversary of the Sept. 11 terror attacks.
Prime Minister Manmohan Singh urged all Indians to come together to defeat terrorism.
"This is a cowardly act. We will deal with it, we will not succumb to pressure of terrorism," he said in Dhaka, the capital of Bangladesh, where he was on a bilateral visit.
"This is a long war in which all political parties, all people of India should stand united so that the scourge of terrorism is crushed," Mr. Singh said.
Federal officials said it was too early to determine who was behind the bombing, the deadliest attack in this nation's capital in almost three years. The blast followed coordinated bomb attacks in July that killed 26 people in Mumbai.
U.K. Bansal, special secretary for internal security, said the bomb created a large crater in front of the courthouse and noted that two of the injured were in very critical condition.
He said a preliminary examination of the blast site and the bomb's remnants suggest that nitrate-based components with traces of PETN were used.
PETN is a hard-to-detect explosive that was used in the attempted 2001 shoe-bomb and 2009 underwear-bomb airliner attacks in the U.S.
Police said the explosion was caused by a homemade bomb and released sketches of a suspect.
India issued a nationwide alert after the blast, and security was heightened across the country, especially in key places such as airports, railway stations and utilities.
The bomb exploded near Gate No. 5 of the High Court, which is about 2 miles from the Indian parliament building.
"The blast occurred outside the High Court in the public area where unchecked people come," a senior police official said. "Apparently the bomb was in a briefcase."
As the bomb exploded, people covered in blood were seen running for their lives.
"I saw several dismembered bodies. There were people with severed limbs crying in pain," an eyewitness said.
The Harkat-ul-Jihadi terror group said in an email: "We owe the responsibility of today's blasts at high court delhi .... our demand is that Afzal Guru's death sentence should be repealed immediately else we would target major high courts & The Supreme Court of India."
India's Supreme Court different from High Court issued a death sentence for Afzal Guru, who hails from the disputed Kashmir region, which India controls, for his role in the attack on the Indian parliament in 2001. His petition for clemency is awaiting a decision by Indian President Pratibha Patil.
Indian Home Minister Palaniappan Chidambaram said in parliament soon after the blast that the perpetrators would be tracked down and brought to justice.
New Delhi police weathered media criticism after the blast because a small explosion occurred in the same place in May.
Indian media said no closed-circuit TV cameras were installed nearby and no metal detectors were at the site, where nearly 200 people were standing in a line for passes to enter the court premises.
"Intelligence pertaining to threats emanating from certain groups was shared with Delhi police in July 2011," Mr. Chidambaram said.
"In the last few years, several measures have been taken to strengthen Delhi police. Despite the capacity that has been built and despite Delhi police remaining on high alert, the tragic incident occurred today," the minister said.
He said the probe has been handed over to India's National Investigation Agency (NIA).
Ajai Sahni, a counterterrorism expert with the New Delhi-based Institute for Conflict Management, said such attacks cannot be prevented without proper action by police.
"You cannot prevent [this] in the wider urban theater [if] you do not act on the ground and build nationwide capacity of the police force," Mr. Sahni said.
"India is displaying a great deal of symbolism with [its] creation of higher anti-terror institutions but not doing anything on the ground where it is required most," he added. "Database or CCTV cameras cannot prevent attacks. It is always possible to find a blind spot. The police force across the nation has to be made capable."