A leader of a small Pakistani Shiite Muslim group has been shot dead in the southern city of Karachi.

Police say Sardar Hussain Jafri, who headed the little-known group called the Voice of Shia, died on the spot.

A person who identified himself as Riaz Basra, leader of the extremist anti-Shiite group, Lashkar-e-Jhangvi, phoned the BBC shortly after the attack to claim responsibility.

If confirmed, it will be the latest in a long series of religiously motivated killings in Pakistan.

Most of the recent victims have been Shiite Muslims, in a country where the majority of Muslims are Sunnis. About a thousand people have died in the past ten years of sectarian violence between the two communities.

From the newsroom of the BBC World Service