Türkiye has formally arrested at least 25 suspects connected to the shooting of a man during a service at an Istanbul church last weekend, according to the Justice minister.

Among the 25 remanded in custody were the two suspected gunmen, previously captured by police, who are believed to be tied to Daesh, Yılmaz Tunç said on the social media platform X.

The two main suspects were foreign nationals, one from Tajikistan and the other Russian, Interior Minister Ali Yerlikaya said previously.

Daesh claimed responsibility for the attack in a statement on Telegram, saying it was in response to a call by the group's leaders to target Jews and Christians.

Tunç said the 25 suspects were charged with membership of an illegal organization and aggravated intentional homicide, adding that another nine suspects were released pending trial.

The attack took place on Sunday morning at the Italian Santa Maria Catholic Church in Istanbul's Sarıyer district. One Turkish citizen – who was targeted by the gunmen – was killed while attending the service.

The murdered man, Tuncer Murat Cihan, had gone into the church while out for a walk and had no political or religious affiliations, his cousin has said. Authorities have said the attack could have been deadlier if not for a jammed weapon.

Istanbul Mayor Ekrem Imamoğlu said the Polish consul general was also inside the church with his family during the attack. On Sunday, President Recep Tayyip Erdoğan called the Polish diplomat and the church's priest to offer his condolences.

Still reeling from the attack, the clergy of Santa Maria opened their doors to the press on Monday and mass resumed on Thursday. Pews and walls were peppered with bullet holes. A bouquet was left where Cihan was killed.

CCTV footage from the inside of the church, verified by Reuters, showed the masked gunmen entering the building and shooting the man who was walking in front of them.

Turkish police said two gunmen drove a car brought from Poland to Istanbul a year ago, which had not been used until the day of the shooting.

Local media also wrote, that among the suspects detained, an Andrei Guzun could be the instigator of the attack, who they claimed was one of Daesh’s so-called Türkiye ringleaders who authorized his underlings to carry out attacks in the country.

Another suspect, M. Alisher Ugli Mirzoev, was working to set up training grounds at a farm in Istanbul to raise Daesh members that would be sent to the U.S., reports said.

They also alleged the "independent" behavior of the Daesh members indicated they belonged to the terrorist group's "lone wolf" division, which includes operatives trained to act of their own volition.

Lone wolves of Daesh are responsible for the killing of 50 people on June 12, 2016, at a Florida nightclub and the killing of 84 people in France's Nice when a truck plowed through a crowd. In Türkiye, Abdulkadir Masharipov, a lone wolf of Kyrgyz origin, slaughtered 39 people in a popular Istanbul nightclub as revelers gathered to welcome the New Year on Jan. 1, 2017.

Türkiye took possession of a valued database of Daesh, containing names and information about 9,952 lone wolf terrorists after a successful operation carried out in the past months by police in Istanbul. The database was first in possession of Daesh leader Abu Bakr al-Baghdadi, who was killed on Oct. 27, 2019.

Daesh remains the second biggest threat of terrorism for Türkiye, which faces security risks from multiple terrorist groups and was one of the first countries to declare it as a terrorist group in 2013.

In December last year, Turkish security forces detained 32 suspects over alleged links with Daesh who were planning attacks on churches and synagogues, as well as the Iraqi Embassy.

Daesh extremists have not previously targeted places of worship on Turkish soil but they have carried out a string of attacks, including against a nightclub in Istanbul in 2017 that left 39 people dead and a 2015 bombing attack in Ankara that killed 109.

Turkish authorities have detained 2,086 people suspected of ties to Daesh since June 2023, Yerlikaya has said.

On Thursday, the interior minister said another 15 suspects linked to Daesh were detained in the capital Ankara and assured operations would continue "ceaselessly."