A suicide bomber in the eastern Pakistani city of Lahore has killed at least 20 people and wounded 60, most of them police officers.
The explosion targeted a group of police gathered outside the High Court building, officials said.
A number of people - police and civilians - were seen lying motionless in the street.
Bodies on ground
The police officers were gathering outside the court building ahead of a protest by lawyers against the rule of President Pervez Musharraf.
Police officials said that the bomber blew himself up when police asked him to stop.
"I was in the court when the blast went off. It was a big bang," lawyer Syed Zulfiqar Bokhari told the Reuters news agency.
"I saw bodies of policemen lying on the ground," he said.
There was no immediate claim of responsibility for the attack.