A bomb explosion in a mosque packed with hundreds of worshippers in southern Iran killed at least nine people and injured more than 100 on Saturday, local media reported. The semi-official Fars news agency said the explosion in the city of Shiraz went off as a cleric was delivering his weekly speech against extremist Wahabi beliefs and the outlawed Bahai faith. The report said nine people were killed and 105 injured, some of them critically. The force of the explosion shook houses more than a kilometer (a mile) away and ambulances and firefighters were rushing to the mosque, it said. Officials urged the public to donate blood and called all nurses in the city in on duty. A police official said a homemade bomb caused the explosion, Fars reported. It also quoted a young woman who was there as saying some 800 worshippers were inside the mosque at the time of the explosion. Bombings are unusual in Shiraz, a major draw for foreign tourists who come to see the ruins of nearby Persepolis, an ancient Persian kingdom that was a center for ceremonies and worship. No one claimed responsibility for the attack. Iran has faced several ethnic and religious insurgencies that have been behind rare but deadly attacks in recent years - though none have amounted to a serious threat to the government.