Syria's Interior Ministry says the sleeper cell behind a deadly church explosion near Damascus belonged to the Islamic State group.

Syrian authorities on Monday announced arrests over a suicide blast targeting a church blamed on the Islamic State group, as President Ahmed al-Sharaa vowed those involved in the "heinous" attack would face justice.

DAMASCUS (Reuters) -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.