A helicopter crashed and broke apart in a wooded area Wednesday, injuring the four people on board, an official said.

Some people at a construction site near the crash were also injured by flying debris, said Harris County Sheriff's official Lt. John Martin.

Martin said he had no information about the kind of helicopter or where it was going.

Two of the people on board with serious injuries were transported to a Houston hospital by helicopter, Martin said. Two others with less serious injuries were taken to a local hospital.

The area of the crash was about 16 miles west of Houston's Bush Intercontinental Airport (search).