Istanbul police detained 40 Daesh suspects in counter-terror raids carried out in the city's Fatih district on Saturday.

Police raided 23 addresses in Fatih and captured documents and digital material related to Daesh terrorists.

According to reports, the suspects are foreign nationals from Azerbaijan, Iran, Iraq and Afghanistan, who have links to the terrorist group.

Some of them have reportedly been to conflict sites in Syria.

Turkey strengthened security measures throughout the country following a deadly shooting and triple suicide bombing attacks on Istanbul's Atatürk Airport on June 28 and persistent rocket attacks from across the border in Syria.

Since 2011, Turkey has deported more than 3,290 foreign terrorist fighters from 95 countries and refused more than 38,269 individuals' entry to Turkey in its fight against Daesh, which counts the Muslim-majority country as an enemy. Daesh is responsible for a string of terror attacks in Ankara and Istanbul, as well as cross-border fire from Syria that has killed a number of residents in Turkish border towns over the last year.