Bloomberg reports that at least 11 people are dead and scores injured after a briefcase bomb exploded outside the capital's high court.

With the government ordering a state of high alert, the Press Trust of India says a Pakistani militant group has claimed responsibility.

"It was a devastating scene," said a lawyer who was working at the court.  "I saw bodies, people with broken arms and legs and flesh on the floor."

In July, 25 people were killed in attacks on Mumbai, India's most populous city.

Another lawyer in Delhi said: "This is a lapse of police security.  It could happen again tomorrow."

The Wall Street Journal said the blast will heighten "concerns about the nation's security vulnerabilities".