A senior hospital official says at least 20 people were killed in the hours-long siege of a Shiite Muslim mosque in the Afghan capital of Kabul.

Mohammad Salim Rasouli, chief of Kabul's hospitals, said at least 50 more were wounded, many of them children.

The mosque was packed with worshippers attending Friday prayers. Friday is the Muslim sabbath when worshippers usually attend prayers at the mosque.

Rasouli said the death toll could rise because many of the wounded were seriously hurt.