Eleven people were killed on Saturday and 46 injured when a Turkish intercity bus taking families bound for a half-term skiing trip crashed into trees while travelling on a motorway, local officials said.

The bus, which was making an overnight journey from the capital Ankara to the western city of Bursa, crashed in the region of Eskisehir amid good road conditions, Eskisehir governor Ozdemir Cakacak was quoted as saying by the Dogan news agency.

The road was empty and neither wet nor frozen, Cakacak said, vowing that the causes would be made clear.

Dogan reported that the passengers on the bus were mainly families with their children who were going to Bursa to spend the upcoming half-term at the popular Uludag ski resort.

It said the passengers were on a special all-inclusive promotion offered by the bus company to spend the week at the ski resort before returning to Ankara.

The news agency did not say if any children were among those killed. Identification of the bodies was in progress.

The two drivers, who were both lightly injured, have been detained and prosecutors launched an investigation, Dogan said.

The driver who was at the wheel at the time of the crash, has denied any wrongdoing.

"I saw a dark shape which I thought was a dog," Dogan quoted him as saying.

"I went to the right but the bus went out of control and hit a tree... I was not going fast, I was not sleeping, it was a matter of an instant," the man added.

Turkey has a dire road safety record with over a million accidents in 2016 and 7,300 people losing their lives, according to official statistics.