This assault marks a shift in tactics aimed at destabilizing civil peace and inflaming sectarian tensions. Interior officials said early evidence points to Islamic State sleeper cells, although no group has claimed responsibility.

DAMASCUS, June 23 (Xinhua) -- A suicide bombing during Sunday evening Mass at a Damascus church killed at least 22 people and wounded 63 others, marking the deadliest and first attack of its kind on a Christian place of worship in the Syrian capital in several years, officials said.

According to Syrian authorities, two attackers stormed Mar Elias (St. Elias) Orthodox Church in the predominantly Christian Dweilaa neighborhood, opened fire on worshippers, and detonated explosive belts near the entrance.

The Britain-based Syrian Observatory for Human Rights confirmed the death toll and reported that women and children were among the victims.

"This was a condemned terrorist act. We first heard gunfire in the courtyard, then two men entered, fired on the congregation, and blew themselves up. Such a crime violates every religion and every shred of humanity," said parish priest Melatios Shtah.

"They were yelling sectarian slogans while shooting. Then everything went dark after the explosion," Worshipper Lawrence Maamari told Xinhua about the panic inside the church.

Authorities sealed off the area and urged residents to keep roads clear for emergency vehicles, while hospitals issued urgent calls for blood donations.

The observatory called the bombing a "dangerous escalation," noting that previous attacks on Christian sites in Syria during the civil war were largely acts of looting or sabotage, especially in areas once controlled by the Islamic State (IS).

This assault marks a shift in tactics aimed at destabilizing civil peace and inflaming sectarian tensions, it added.

Interior officials said early evidence points to Islamic State sleeper cells, although no group has claimed responsibility.

Political analyst Mohammad Nader Al-Omari said the attack may have been timed to exploit regional instability following a recent U.S. strike on Iran.

Information chief Hamzah al-Mustafa condemned the bombing as a "cowardly act meant to undermine national cohesion" and pledged that those responsible would be brought to justice.

Damascus has been largely free of major attacks since government forces reclaimed surrounding areas in 2018. Sunday's bombing shattered that calm and renewed concerns over the resurgence of IS in southern and eastern Syria.

"The state will not allow criminals to destabilize society," Mazhar al-Wais, the country's justice affairs chief, said on X, vowing swift and fair trials for those behind the attack.