At least 15 people have been killed and about 50 injured in a bomb attack on a Shiite mosque in Zahedan in southeastern Iran.

The bomb exploded during evening prayers on the feast-day commemorating the death of Fatima, the Prophet Muhammad's daughter.

Zahedan is the capital of Iran's Sistan-Baluchestan province and the city is close to the borders of both Pakistan and Afghanistan. Local Iranian police are often caught up in clashes with drugs smugglers and extremists.