The vehicle, believed to be a lorry, was travelling on a highway in the Izmir region close to Izmir airport when it flipped over and fell into the channel several metres below
Nineteen people, including children, died on Sunday when a vehicle carrying migrants reportedly heading for EU member Greece plunged off the highway into a waterway in western Turkey, state media said.
The vehicle, believed to be a lorry, was travelling on a highway in the Izmir region close to Izmir airport when it flipped over and fell into the channel several metres below, state-run Anadolu news agency said.
The nationality of the migrants was not made clear. Nineteen people were killed, the agency said, lifting an earlier toll of 15, while 11 more were wounded.
Turkish television pictures showed the stricken wreckage of the vehicle, which was reduced to burned-out metal by the impact of the crash.
Large numbers of emergency service personnel were sent to the scene.
The DHA news agency said that the vehicle was headed for the coast of the Izmir region, from where the migrants planned to take a boat to Greece's Samos island.
Samos is just a few kilometres north of Turkey's Dilek peninsula that juts out from the Izmir region.
Turkey is a key transit points for migrants from troubled countries in the Middle East, Asia and Africa seeking a new life in Europe.
A million migrants crossed from Turkey into Greece in 2015, mostly by boats, in a crisis which forced a deal between Ankara and the EU to stem the flow of people.
Numbers have fallen since but people are still undertaking what is a highly perilous journey.
According to UN figures, more than 24,500 migrants have arrived in Greece by sea so far this year, with 118 people losing their lives via this route.