At least 20 people have been killed and 52 more are injured in a “terrorist attack” on a church in the Syrian capital on Sunday, according to the country’s health ministry.

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.

Syrian Christians were struggling on Monday to understand why their community was targeted in a suicide attack and whether they can rely on the Islamist-led government's assurances of protection.