A suicide car bomb attack on a police intelligence unit in Lahore has killed at least 13 people and wounded 60 this morning.
A doctor at the hospital treating victims said the dead included a woman and a child.
The blast left a huge crater in the road outside the office of the main police investigation agency, the Federal Investigation Agency, and destroyed the front of the building.
The office was used to interrogate suspected militants and it has been attacked at least twice before.
A spokesman for the Tehreek-e-Taliban group has claimed responsibility for the suicide attack.
'We claim responsibility for the Lahore blast. We will continue such attacks in future,' Tehreek-e-Taliban Pakistan (TTP) spokesman Azam Tariq told two reporters in telephone calls from an undisclosed location.
'The attack was to avenge (US) drone attacks and (Pakistani) military operations in the tribal areas. We will carry on such attacks as long as drone strikes and operations continue.'
US drone attacks routinely target Taliban and al-Qaeda commanders in Pakistan's semi-autonomous tribal belt, which lies on the border with Afghanistan, and the US calls the global headquarters of al-Qaeda.
Pakistan's military claims to have made big gains against Taliban and al-Qaeda strongholds over the past year, following major offensives in the northwestern district of Swat and the tribal region of South Waziristan.