"Our hope is that there are no other victims," he said.
It wasn't immediately clear if a signaling problem caused the crash. Sahin said a technical inspection has begun while NTV television, quoting unnamed officials, said three prosecutors were assigned to investigate.
In July, 10 people were killed and more than 70 injured when most of a passenger train derailed in northwestern Turkey, after torrential rains caused part of the rail tracks to collapse. Last month, 15 people were injured when a passenger train collided with a freight train in Turkey's central province of Sivas.
Konya, about 260km south of Ankara, is home to the tomb of the Sufi mystic and poet Jalaladdin Rumi, attracting thousands of pilgrims and tourists.
- AP