A total of 21 people were killed in Friday's explosion that targeted a mosque in the Saudi governorate of Qatif, spokesman for the health department at the eastern region Assad Saud said.

Twenty one people died from a total of 102 injured in the blast, he explained.

Health Minister Khaled al Falih and head of the health department in the province have followed up the situation at Qatif central hospital, Saud further said.