A bomb blast has killed at least 20 people in a neighbourhood dominated by Shiite Muslims in the southern Pakistani city of Karachi.
Police official Azhar Iqbal said the bomb exploded today outside a Shiite mosque as people were leaving evening prayers.
He said initial reports suggest the bomb was rigged to a motorcycle, but a survey of the damage indicates there could have been additional explosives planted at the scene.
Several buildings nearby caught fire.
A top government official Taha Farooqi said 20 people were killed and others are feared dead. He says more than 50 were wounded.
No one has claimed responsibility, but Sunni militants linked to al-Qaida and the Taliban have targeted Shiites in the past, claiming they are heretics.