A number of patients had to be evacuated after a fire broke out at a hospital in Istanbul on Thursday, AP reported. There were no immediate reports of any casualties.

Footage from local television channels showed flames engulfing a facade of the Taksim Training and Research Hospital in Gaziosmanpasa district on the European side of the city. Thick black smoke was seen rising as firefighters tried to control the blaze even several hours after it started on the hospital’s roof, CNN Turk reported.

The fire has been almost brought under control, Mayor of Gaziosmanpasa Hasan Tahsin Usta told CNN Turk.

Several explosions were heard at the scene, according to Russian news outlet RT. The cause of the fire is not known yet.