He said the mosque had been swept by investigators on Friday and that nothing suspicious was found at that time.

Footage from the eNCA TV news network showed a large police presence at the mosque and worshippers and bystanders gathered outside, hundreds of metres away behind police tape.

Prem Balram, a spokesman for Reaction Unit SA, a private emergency service, was quoted on the News24 online news service as saying the mosque and homes in the area were evacuated "after a device resembling a bomb has been found inside the building".

Three men armed with guns and knives attacked worshippers at the mosque near Durban on Thursday. One person was killed after his throat was slit, and two others were injured.

No arrests have been made yet in connection with that attack, Mhlongo said.