The gunman opened fire at the crowd gathered at the mosque for prayer.
The two injured in their backs have already been transported to a hospital.
The attacker reportedly escaped from police. The police has cordoned off the area and is conducting investigation.
According to Hurriyet newspaper, an person entered the mosque and opened fire on his father. The suspected attacker's father and a man praying nearby were injured.
The attack comes after nightclub Reina in Istanbul's Besiktas district was attacked early on Sunday by a man, who was reportedly talking in Arabic. The attacker is said to have opened fire from a Kalashnikov assault rifle.
At least 39 people were killed, including 16 foreigners, and 69 injured as a result of the attack, according to the Turkish Interior Ministry.
