According to preliminary reports, the explosion was caused by a bomb.
At least one person was killed and six injured in an explosion in Istanbul.
"The cause of the blast is still unclear, all versions are being considered," Habertürk TV channel reports citing Istanbul governor Vasip Şahin as saying.
A large number of ambulances and firefighters arrived at the scene. All train services have been suspended.
Dozens of people have been evacuated, based on tweets from the scene, as officials investigate into the situation.
The area of the accident is a residential and industrial neighborhood on the European side of Istanbul.