The arrests in the dawn raid, by a counter-terror police squad in the Basaksehir district on the European side of the city, brought the number of people detained in the investigation to 24, it said.
A police spokesman could not confirm the report, which was also carried by other media.
Three suspected Islamic State suicide bombers killed 44 people in a gun and bomb attack at Istanbul's main airport on Tuesday, the deadliest in a string of attacks in Turkey this year.
The suspected suicide bombers were Russian, Uzbek and Kyrgyz nationals, a Turkish government official said on Thursday.
Separately, security forces on Wednesday detained four Turkish citizens at the Oncupinar border gate in southeast Turkey on suspicion of membership in a terrorist group, the local governor's office said in a statement.
The four were attempting to return to Turkey from a conflict zone in Syria under Islamic State control, it said.