A powerful bomb ripped through a packed reception area at the entrance to New Delhi's High Court on Wednesday, killing nine people and injuring 62, many of them petitioners waiting for their cases.
Police said the device had apparently been placed in a suitcase near the reception where more than 100 people were queueing for their entry passes to the court complex, located in the centre of the Indian capital.
The court buildings were evacuated as police blocked off the area and emergency services rushed the injured, some of them in a critical condition, to hospital.
"Nine people have been confirmed dead. The number of injured is now 62," Delhi police spokesman Rajan Bhagat told AFP.
The explosion occurred around 10:15 am (0445 GMT). There was no immediate claim of responsibility.
Condemning the attack Prime Minister Manmohan Singh said India would not be bowed by terrorism.
"This is a cowardly act of a terrorist nature," Singh, who is currently on a visit to Bangladesh, told television reporters in Dhaka.
"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."
Home Minister P. Chidamabaram, in a statement to parliament, called on people to remain "resolute and united" in the face of efforts to destabilise the country.
One police source said initial investigations suggested the bomb had contained potassium nitrate.
"More than 100 people were in a queue at the reception," Rahul Gupta, a petitioner whose case was listed for a hearing Wednesday, told AFP.
"Then there was a huge explosion. I saw a lot of people lying around in a pool of blood."
It was the first major attack on Indian soil since triple blasts in the financial capital Mumbai on July 13 killed 26 people. Those attacks remain unresolved.
The Indian capital was targeted in September 2008 by a series of blasts that killed 22 people and injured nearly 100 in an upmarket shopping area.
A home-grown militant outfit called the Indian Mujahideen claimed responsibility for that attack.
The High Court was previously targeted in May this year when a low-intensity device was set off in the parking lot. There were no casualties and only minimal damage.
Rajesh Gupta, a 45-year-old businessman was among those queueing for a court pass when Wednesday's bomb went off.
"My hand was injured. My colleague suffered a serious injury in his leg, he has been taken to hospital," Gupta said.
"The area was very crowded, there must have been some 200 people there."The scene here is total chaos. People are really frantic and worried about their friends and loved ones," he added.
One lawyer inside the court told AFP how he was working in his office when the bomb detonated.
"I was in my chambers when I heard a huge explosion and the windows in my room were blown in," M.I. Chowdhary said.
"People were carrying the injured away. Some of them looked horribly hurt.
"That time is peak hour for petitioners and other people getting their entry passes at the reception area. So it seems somebody had timed it to cause maximum casualties.
"Security is really not up to the mark," Chowdhary said. "It needs to be tightened around such a sensitive target."
Other recent bombings in India include a blast in February last year at a packed restaurant in the western city of Pune, which killed 16 people including several foreigners.
In 2006, a series of seven high-powered blasts on suburban trains in Mumbai killed 187 commuters and left 800 injured -- an attack that India blamed on Pakistan-based militants.