State news agency Anadolu said five wagons came off the tracks as a result of the incident on Sunday in a region near the Greek border. The train was carrying 362 passengers and was headed to Istanbul.
According to state-run TRT Haber television, the train, with over 360 people on board, was travelling from Kapikule on the Bulgarian border to Istanbul when six of its carriages derailed in the Tekirdag region.
Over 100 ambulances have been sent to the scene, TRT Haber said, quoting Health Ministry Undersecretary Eyup Gumus. The Turkish army said in a statement that it had sent helicopters to the scene.
Television pictures showed several train carriages laying on their sides, and shocked injured being taken away on stretchers.
“There are a large number of injured and we have fatalities,” Tekirdag Governor Mehmet Ceylan told the NTV channel. “The accident happened because of adverse weather conditions,” he added.
Reports said the surrounding area was muddy due to recent rains.
President Recep Tayyip Erdogan has been informed over the accident and expressed his condolences over those who lost their lives, state-run Anadolu news agency said.
Turkish authorities under Erdogan have over the last years sought to modernize Turkey’s once ramshackle rail network, building several high speed inter-city lines.
The train involved in the accident appeared to be one of the slower passenger trains travelling on a single track railway.