A bomb blast at a mosque in northern Afghanistan killed at least one worshipper and wounded seven others during Friday's midday prayers, police said.

Provincial police spokesman Qari Obaidullah Abedi said one worshipper had been killed in the blast at Alif Birdi mosque in Imam Shahib district.

"The explosives were placed inside the mosque. The blast occurred when worshippers were offering Friday prayers," he told AFP.

A medic at the provincial hospital confirmed the toll of dead and wounded.

No group has so far claimed responsibility for the attack.