A five-storey apartment building collapsed in Istanbul, Turkey, early Wednesday, killing at least two people and injuring more than two dozen others, authorities said.

A city worker who walked by shortly after midnight saw the building swaying and alerted people inside by shouting and throwing stones at the windows, said Istanbul Mayor Kadir Topbas. Some people managed to safely flee, but the dead and injured had become trapped on a stairway as the building toppled, said Ali Karahan, chief of Istanbul firefighter department.