Five people were killed in an explosion at a mosque of the Alawite minority sect in the Syrian city of Homs on Friday, Syrian state news agency SANA said.
SANA cited Syrian Health Ministry official Najib al-Naasan as saying 21 others were wounded and that the figures were a preliminary toll, indicating they could rise.
Homs city's press office said an explosive device had detonated inside the Imam Ali bin Abi Talib mosque and that security forces had cordoned off the area.
Local official Issam Naameh told Reuters the blast took place during Friday noon prayers, typically the busiest time for mosques.
Syrian state media SANA published footage of rescuers and security forces examining debris splayed across the mosque's green carpet. There was no immediate claim of responsibility for the attack.
Syria has been rocked by several episodes of sectarian violence since longtime leader Bashar al-Assad, an Alawite, was ousted by a rebel offensive last year and replaced by a government led by members of the Sunni Muslim majority.
Earlier this month, two American soldiers and a civilian interpreter were killed in central Syria by an attacker described by the authorities as a suspected member of the Islamic State, a violent Sunni Muslim group.
