(Reuters) - Ten people suffered non-life threatening injuries in New York on Sunday when a crane dropped a heating and air conditioning unit being loaded onto a Manhattan building, sending it crashing into the street 30 stories below, the fire department said.

The incident occurred at 10:45 a.m. while workers were using a crane to raise an HVAC unit to the roof of a building in the 200 block of Madison Avenue near East 38th Street in Midtown, New York City Fire Department spokeswoman Elisheva Zakheim said.

The unit broke free from the cable and bounced several times along the building's facade before landing in the middle of the street, Zakheim said.

"Thank God, this incident occurred at an hour of the day on a weekend when there were not too many people around," said Mayor Bill de Blasio in televised remarks.

Ten people were taken to the hospital and were in stable condition with non-life threatening injuries, the department's Twitter feed said.

It was not immediately clear how they were injured, and Zakheim said the incident is under investigation.

Sunday's incident comes a month after a man was killed by a mechanical crane attached to a flatbed truck at a Midtown Manhattan construction site. On April 24, a worker was pinned to the ground between the crane and the truck when the vehicle's hydraulics malfunctioned, according to city officials.

(Reporting by Brendan O'Brien in Milwaukee; Editing by Sandra Maler)