The attack took place Sunday inside the Mar Elias Church in Dweil’a, on the outskirts of Damascus city. The Syrian Interior Ministry said a fighter from the ISIS group entered the church and fired at the people there before detonating an explosive vest he was wearing.

A source, who requested anonymity, said two men were believed to be involved in the attack, including the bomber. Another source said the incident marks the first suicide bombing in Damascus since Bashar al-Assad was toppled by an Islamist-led rebel insurgency in December, but there had been previous plots targeting churches in Syria.

The Syrian foreign ministry said the attack was an attempt to undermine coexistence in the multi-sectarian, multi-ethnic country.