Sunday’s suicide bomb attack on a Greek Orthodox Church service in Damascus, which Syrian officials have blamed on the Islamic State (ISIS), is raising concerns that the war between Iran and Israel, now joined by the United States, is creating opportunities for the jihadi group that once governed large swathes of Syria to exploit a security vacuum left by the fall of the Assad regime. 

At least 25 people were killed and 60 others injured after an assailant opened fire on the congregation at the Mar Elias Church in Dweila, a neighborhood in Damascus, before detonating an explosive vest. Eyewitnesses inside the church said a second gunman who did not blow himself up had also taken aim at dozens of worshippers as they prayed. 

Syria's interim president, Ahmed al-Sharaa, declared three days of national mourning for the victims of the atrocity and ordered an emergency investigation as condemnations poured in from across the globe. “We will work night and day, mobilizing all our specialized security agencies, to capture all those who participated in and planned this heinous crime and bring them to justice,” Sharaa said in a Monday statement. 

Syria's state-run SANA news agency reported Monday evening local time that security forces in the Damascus countryside arrested “a number of criminals” involved in the church attack.