DAMASCUS - A suicide bomber stormed a crowded church in the Syrian capital Damascus during Sunday mass, opening fire on worshippers before detonating his explosives, killing at least 19 people and injuring dozens more, security sources and a monitoring group said.

The Syrian health authorities put the latest official death toll at 13, with 53 others wounded.

The blast ripped through the Mar Elias Church in the Dweilaa district, a predominantly Christian neighborhood on the eastern outskirts of Damascus, leaving behind blood-stained pews, shattered icons, and scenes of chaos, according to eyewitnesses and local media.

The Syrian Observatory for Human Rights said the attacker opened fire inside the packed church before blowing himself up, causing "severe human losses." The monitoring group reported that the toll may rise given the critical condition of many of the injured.

Authorities from the interior security department confirmed that the perpetrator was affiliated with the Islamic State (IS). In a statement posted on X, interior chief Hamzah Al-Mustafa condemned the "cowardly terrorist act". He emphasized that "such acts are contrary to the values of citizenship that bind Syrians together," and reaffirmed the state's commitment to national unity, equal citizenship, and defeating criminal groups that threaten public safety.

Emergency responders cordoned off the area as ambulances rushed the wounded to Damascus hospitals. Authorities urged citizens to avoid the vicinity to allow medical teams to operate freely and prevent further casualties amid fears of additional attacks.

READ MORE: Syria releases dozens of detainees cleared of war crimes charges

The blast is the first of its kind targeting a church in Damascus in several years, sparking renewed concerns about sleeper cells operating in the capital.