Twenty-four people were killed and more than 70 were injured when a train packed with weekend passengers derailed in northwest Turkey, Deputy Prime Minister Recep Akdag said on Monday.
The state-run Anadolu news agency quoted Mr Akdag as saying search operations at the site of the wreck of the train, which derailed on Sunday evening in the Tekirdag region while heading towards Istanbul, were complete.
The train, with more than 360 people on board, was travelling from the Edirne region on the Greek and Bulgarian borders to Istanbul's Halkali station when six of its carriages came off the rails.
Health ministry undersecretary Eyup Gumus told state-run news agency Anadolu that more than 100 ambulances were sent to the scene.
The Turkish army said that it had sent helicopters, while the Istanbul municipality on Twitter said 24 rescue workers and six vehicles were sent to assist.
Television pictures showed several carriages lying on their sides, and the injured being carried away on stretchers as rescue workers picked through the wreckage.
“The accident happened because of adverse weather conditions,” Tekirdag governor Mehmet Ceylan told the NTV channel.
Reports said the surrounding area was muddy following heavy rain.
Officials confirmed that rainwater eroded the ground beneath the tracks, causing the train to derail.
The train derailed outside the village of Sarilar in Corlu district, reports said.
President Recep Tayyip Erdogan expressed his condolences to the families of those killed in an accident that has "deeply upset the whole nation".
Mr Erdogan said all state institutions were "using every means available to help", as he vowed that there would be a comprehensive investigation into the "tragic accident".
Turkey’s audiovisual authority RTUK later said the government has issued a temporary ban on broadcasting images from the scene.
Turkish authorities under Mr Erdogan have over the last years sought to modernise Turkey's rail network, building high speed inter-city lines.
Turkish passengers have in general preferred taking planes or the bus for inter-city travel, but this is changing with the new high-speed lines.
The train involved in the accident appeared to be one of the slower passenger trains travelling on a single-track railway.
Turkey’s network has suffered several fatal accidents in recent years.
In January 2008, nine people were killed when a train derailed in the Kutahya region south of Istanbul because of faulty rails.
And in Turkey’s worst recent rail disaster, 41 people were killed and 80 injured in July 2004 when a high-speed train derailed in the north-western province of Sakarya.