A suicide bomber has killed at least 25 people and injured 63 of the 350 congregants after opening fire and then self-detonating at a Greek Orthodox church in Syria on Sunday.

More than 22 people were killed and another nearly 60 were injured when an Islamic State suicide bomber attacked a church in the Syrian capital of Damascus, officials said.

The interior ministry says a man affiliated with IS entered a church and opened fire before blowing himself up.