Eight people have been killed and 50 others wounded in an explosion in the southern Iranian city of Shiraz, a national news agency has reported.
The explosion on Saturday was caused by "a powerful bomb at Shiraz's Mosque of the Martyrs after evening prayers," a report by Fars news agency said, citing city officials.
The death toll is expected to rise due to the severity of some people's injuries, officials have said.
Mohamed Hasan al-Bahrani, Al Jazeera's Tehran bureau chief, said that available information says that a bomb detonated in the mosque after Maghreb and Isha prayers.
The explosion took place in the section where males were praying, according to reports.
Shiraz is close to a number of ancient sites popular with tourists.
No group or individual has claimed responsibility for the explosion.
The last major bombing in Iran occurred in the south-eastern city of Zahedan in February 2007.
Thirteen members of Iran's elite Revolutionary Guard died in that blast, with Sunni fighters blamed for the attack.
PHOTO CAPTION
Map of Iran locating the city of Shiraz
Al-Jazeera