NEW DELHI -- A powerful bomb hidden in a briefcase ripped through a crowd of people waiting to enter a New Delhi courthouse Wednesday, killing 11 people and wounding scores more in the deadliest attack in India's capital in nearly three years.
An al-Qaida linked group claimed responsibility for the blast outside the High Court, though government officials said it was too early to name a suspect. The attack came despite a high alert across the city and renewed doubts about India's ability to protect even its most important institutions despite overhauling security after the 2008 Mumbai siege.
"Have we become so vulnerable that terrorist groups can almost strike at will?" opposition lawmaker Arun Jaitley asked in Parliament.
The bomb left a deep crater on the road and shook the courthouse, sending lawyers and judges fleeing outside.
"There was smoke everywhere. People were running. People were shouting. There was blood everywhere. It was very, very scary," said lawyer Sangeeta Sondhi, who was parking her car near the gate when the bomb exploded.
The government rallied Indians to remain strong in the face of such attacks.
"We will never succumb to the pressure of terrorists," Prime Minister Manmohan Singh said during a visit to neighboring Bangladesh. "This is a long war in which all political parties and all the people of India will have to stand united so that this scourge of terrorism is crushed."
The bomb exploded about 10:14 a.m. near a line of more than 100 people waiting at a reception counter for passes to enter the court building to have their cases heard.
Officials said the blast killed 11 people and wounded 59 others. Their identities were not available, but no judges were among the victims.
People ran to the blast site to assist the injured, piling them into auto-rickshaws to take them to the hospital. Ambulances and forensic teams rushed to the scene, along with sniffer dogs and a bomb disposal unit, apparently checking for any further explosives.
Renu Sehgal, a 42-year-old housewife with a case before the court, had just received her pass and was standing nearby with her uncle and mother while her husband parked their car when she heard the explosion.
"The sound was so huge and suddenly people started running," she said. "We were all in such a big panic. ... I'm lucky I survived."
The court building was evacuated after the attack.
The blast probe was quickly turned over to the National Investigation Agency, established after the Mumbai siege to investigate and prevent terror attacks.
Police were scouring the city for possible suspects, searching hotels, bus stands, railway stations and the airport, said top security official U.K. Bansal. All roads out of the city were under surveillance as well, he said.
"We are determined to track down the perpetrators of this horrific crime and bring them to justice," Home Minister Palaniappan Chidambaram told Parliament.
An email sent to several TV news channels claimed the bombing on behalf of Harkat-ul-Jihad-al-Islami, an Islamic extremist group said to be based in Pakistan that was blamed for numerous terror strikes in India. The U.S. State Department says the group has deep ties to al-Qaida, and some of its members have trained at the group's camps.
The email demanded the immediate repeal of the death sentence handed to Afzal Guru, a Kashmiri man convicted for the 2001 attack on India's Parliament, and threatened to target other courts, including the Supreme Court.
"We cannot say anything about the email until we have investigated it thoroughly," NIA chief S.C. Sinha said. "At this point the investigation is fully open and it's not possible to name any group."
The court bombing was the first major terror attack in India since a trio of blasts in Mumbai killed 26 people on July 13. Suspicion for those attacks fell on the shadowy extremist network known as the Indian Mujahedeen, though no one has been arrested.
The bombers struck the court, an appeals panel below India's Supreme Court, even though the capital had been on high alert because Parliament was in session. On May 25, a small explosion that appeared to be a failed car bomb erupted in the court's parking lot.
After the 2008 Mumbai attacks, the government expanded police recruiting and training, set up the NIA and established commando bases across the country so rapid reaction forces could swiftly arrive at the scene of an attack.
Jaitely, in Parliament, said the court bombing raised "deep concern" about "the kind of institutions and systems we have to build to fight this menace."But officials say the number of targets in a nation of 1.2 billion makes it impossible to provide full security.
Dharmendra Kumar, a senior police officer, told reporters the court building itself was strongly protected by police but the explosion hit a busy main road outside.
K.P.S. Gill, a former senior police official, said Kumar's comment showed the police had a "ridiculous mindset" and India needed to rethink its strategy on preventing terror.
"If the public collects there, then you must protect that area," Gill said.
The attack rekindled memories of the string of deadly bombings that rocked the country in 2008, including a series of coordinated bomb blasts in New Delhi on Sept. 13 that killed 21 people. Many of those attacks were blamed on militant groups composed of disaffected Muslims furious at perceived injustices at the hands of India's Hindu majority.
But that violence had mostly abated after the November 2008 siege of Mumbai, when 10 Pakistan-based militants wreaked havoc across India's commercial capital for 60 hours, killing 166 people.
However, a series of smaller attacks raised concerns in recent months that the violence was returning.
Last Sept. 19, two gunmen on a motorcycle shot and wounded two Taiwanese men outside a famous New Delhi mosque. A few minutes later, a bomb rigged to a nearby car malfunctioned and caught fire. On Dec. 7, a bomb exploded in the city of Varanasi, killing a 2-year-old, and a few months later came the failed attack on the High Court in New Delhi.