Two passenger trains have collided in Turkey, killing at least six people and injuring about 70 others in the third major rail accident in a month.
Hundreds of rescue workers and soldiers were sent to the site
The trains crashed into each other head-on near the village of Tavsancil in the north-west province of Kocaeli.
One of the trains was travelling from Ankara to Istanbul, the other from Istanbul to Adapazari.
Rescue teams are at the scene and some bodies are reported to still be trapped in the wreckage.
"The trains are still stuck together, that's why we still don't know the exact number of injured and dead," the Turkish Transport Minister, Binali Yildirim, said.
"The search is continuing," he added. Of the 70 injured, 22 are still hospitalised.
A spokesman for Turkish state railways earlier said one of the trains had apparently passed through a red light.
He added that all the victims were railway staff.
Train 'like an accordion'
The Ankara-Istanbul train was carrying 153 passengers and had nine railway staff on board, Anatolia news agency said.
Details of how many people were on board the second train, an eight-carriage express service, were not immediately available.
"We found ourselves in a cloud of dust. Then I saw people running and yelling... We managed to pull out several people who were trapped," a young man who was on one of the trains told Turkey's NTV television.
Another passenger, Erdem Gosterisli, told CNN-Turk that the first carriage looked "like an accordion".
Scores of rescuers, soldiers and onlookers, as well as dozens of ambulances, rushed to the site of the accident.
Electric saws and axes were used to cut through the sides of the carriages in search for survivors.
On 25 July, 15 people died when a train hit a bus at a crossing in western Turkey.
On 22 July, a newly introduced high-speed train came off the rails between Istanbul and Ankara, near the north-western town of Pamukova, killing 37 people.
The BBC's Steve Bryant in Istanbul says that there have been calls for ministers to resign amid allegations of cost-cutting and poor safety on the country's dilapidated rail network.