Turkish Interior Minister Besir Atalay said the number of detainees could rise as the investigation continues, but did not comment on any links to who was behind the assault that Turkish and U.S. officials called a terrorist attack, The New York Times reported Friday.
Three gunmen and three police officers were killed in the shootout Wednesday at a police guard post outside of the consulate, while a fourth assailant escaped in a car.
"Right now, there are four people under custody," Atalay said Thursday. "Three of them are in Istanbul, and the fourth one was brought from outside Istanbul."
What roles the four detainees may have played in the attack was unclear, the Times said. No one has claimed responsibility for the attack.
Police found an abandoned gray Ford, similar to the car reported driven from the scene, in an eastern neighborhood near the airport, the Anatolian news agency said.
Two armored police buses were stationed outside the consulate Thursday and an American flag flew at half-staff.