Nearly a dozen people were injured Tuesday morning in a fire at a construction site on Fourth Avenue near the corner of 63rd Street in Brooklyn.

Construction workers were trapped as heavy flames and thick smoke were seen from the outside. The smoke quickly spread through the building under construction.

FDNY Deputy Chief Mark Keegan says the calls came in around 8:45 a.m. and about 30 construction workers were inside the building at the time.

"Three of them had to be rescued from the fifth floor using the tower ladder. One from the third floor using the tower ladder. Two other construction workers jumped from the window on to the building next door," says Keegan.

The FDNY says it appears the fire started on the first floor.

Keegan says nine workers and two firefighters were treated for minor injuries.

Workers from the Park Ridge Family Health Center nearby were temporarily evacuated and watched on as the FDNY worked to get the fire under control.