One person died in the attack, which saw two masked gunmen open fire during the Santa Maria Church’s Sunday service, according to Yerlikaya. The incident occurred in the Büyükdere neighborhood around 11:40am local time (3:40aET), Yerlikaya added in a post on X.
According to Istanbul Governor Davut Gul, no other people were injured in the attack.
ISIS has claimed responsibility for a shooting, according to a statement from the ISIS-affiliated Amaq news agency, citing a security source from the terror group.
Two of the arrested suspects are believed to be affiliated with ISIS, Anadalou also reported, describing one as from Tajikistan and the other from Russia, citing the Turkish interior minister.
In the wake of the attack, Turkish security forces with “all their resources” were mobilized, said Turkish President Recep Tayyip Erdogan, in a video posted to social media. The Turkish leader was also seen in a plane holding a phone call with a priest from the targeted church.
The country’s Deputy Chief Public Prosecutor and two other public prosecutors are investigating the incident, according to Turkey’s Justice Minister Yilmaz Tunc.
“The investigation is being carried out in a multifaceted and meticulous manner,” Tunc said.
This is a developing story and will be updated.
Reporting contributed by CNN’s Eyad Kourdi.