The blast, which came from inside a car, occurred in Sancaktepe district on the Asian side of Istanbul, the NTV and CNN-Turk news channels said.
The explosion took place when a military service vehicle was passing the area but initial reports said none of the personnel inside were wounded.
Television pictures showed the vehicle where the explosion took place was almost completely destroyed, with yellow flames rising from the debris.
The explosion comes with Turkey on edge after two deadly attacks in Istanbul this year blamed on Islamic State (IS) jihadists, and a pair of attacks in Ankara that were claimed by Kurdish militants and killed dozens.