Syrian authorities arrested suspects linked to Islamic State after deadly church attack in Damascus that killed 25 people and wounded 63, vowing to bring all perpetrators to justice.

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.

As people were praying during the service, the suspected ISIS attacker entered the church, wearing a mask to cover his face, and opened fire on the Christians.