Dozens of people were killed after a fire ripped through a ski resort hotel in northwestern Turkey on Tuesday, forcing desperate holidaymakers to leap from windows to escape from the flames and smoke.

At least 66 people were killed and 51 injured following the early morning blaze at a hotel in the Kartalkaya resort in Bolu province, according to Turkey’s Interior Minister Ali Yerlikaya. Many children are believed to be among the victims.

As the identities of some of the victims emerged, local schools and businesses started to post death notices for students and educational staff. Some were reported to be fifth graders, aged 10 to 11 years old.

“We are in deep pain. We have unfortunately lost 66 lives in the fire that broke out at this hotel,” Yerlikaya told reporters on Tuesday.

Turkish President Recep Tayyip Erdogan declared Wednesday a day of mourning. “Today is not a day for politics; it is a day for solidarity, for being one and together,” he said on X, adding that anyone found responsible would be held to account.

Officials said some desperate holiday goers had tried to jump out of windows in order to escape, as flames licked the top floors of the facility. Footage of the aftermath showed wreaths of gray smoke swirling around the charred building.

The 12-story hotel was built onto a cliff, complicating efforts to extinguish the flames. Emergency crews arrived at the scene at 4:15 a.m. local time – almost an hour after the fire broke out – at 3:27 a.m. local time, said Yerlikaya. Turkey’s government launched an investigation into the fire, and at least four people have been detained, according to Justice Minister Yilmaz Tunc.

Eyewitnesses recalled the scent of burning, with guests’ screams filling the upper floors of the hotel. Others said the hotel’s fire detection service failed to work. A number of videos, some shared on social media and others broadcast by Turkish TV stations, showed flames coming out of the top floors of the hotel. Some people were seen using tied bed sheets to try to escape the blaze.

“It was so bad. Everybody was jumping out of the windows with the fear of death and people were so ashamed as there were no fire-extinguishers around,” one eyewitness told CNN affiliate CNN Turk.

“We could not get water to people. Ambulances and fire trucks came really late, and people did not know what to do,” the eyewitness added.

A guest staying on the third floor of the hotel said the alarm failed to sound, the Associated Press reported, citing the IHA news agency.

“My wife smelled the burning… We tried to go upstairs but couldn’t, there were flames,” said Atakan Yelkovan. “People on the upper floors were screaming. They hung down the sheets… Some tried to jump.”

The resort is a popular destination for holiday-makers in the winter, especially during school holidays, which run from January until the first week of February. The timing of the blaze fell in the school holidays, when people from Istanbul and Ankara travel to the Bolu mountains to ski.

There were around 234 guests staying at the hotel, Governor Abdulaziz Aydin told the state-run Anadolu Agency. Two of the victims died after jumping out of the building “in a panic,” Aydin said.

At least 30 fire trucks and 28 ambulances were sent to the site, Aydin’s office said. According to Yerlikaya, authorities mobilized 267 emergency personnel to respond to the blaze. Authorities evacuated other hotels at the resort as a precautionary measure, and guests were housed in hotels around Bolu.