Bus blast in Karachi

A bomb has exploded on a bus in the Pakistani city of Karachi killing at least 8 people - all foreigners.

Many of those involved are thought to be Germans.

Another 20 people were injured when the powerful bomb shattered the bus, creating a large crater, witnesses said.

It was not clear who was behind the blast.

Karachi has been rocked by a series of bomb explosions in the past few days following the killing of two members of the ethnic Muttahida Qaumi Movement - which represents Urdu-speakers who migrated from India during the partition of the subcontinent in 1947.