A construction crane cable snapped at a high-rise office building in Midtown Manhattan Sunday as it was lifting an air conditioning unit onto the top of the building, sending the unit plunging nearly 30 stories, the New York Police Department said. Ten people, including two construction workers, were injured, but none of the injuries was considered life-threatening, New York City Mayor Bill de Blasio told a press conference.

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

The equipment fell about 28 stories onto the sidewalk, damaging the building façade on the way down and causing debris to fall onto the sidewalk. 

"Everyone went off of the scene awake and alert and oriented. The two construction workers were taken to the Bellvue trauma center out of an overabundance of caution. The others have been removed to NYU. Everybody is awake and stable at this time," FDNY Assistant Chief Ron Spadafora said.

Emergency crews responded to the scene at 261 Madison Ave., between East 38th and East 39th streets, after a call came in around 10:45 a.m. EDT, officials said.

The crane operator was trying to lift a piece of the industrial-size generator to the roof of the 30 story high-rise building, police told WCBS, New York. The building is currently under construction and unoccupied.

The streets surrounding the area have been closed as emergency responders work at the scene, including Madison Avenue from East 37th Street to East 42 Street; 37 Street between Park Avenue and Fifth Avenue; 38 Street at Park Avenue and 40 Street between Park Avenue and Fifth Avenue.

The city is working to have those streets reopened by the Monday morning commute, de Blasio said.

"We, as I said, will do a full investigation to understand what happened here, and to guard against anything like this in the future," de Blasio said. 

crane Partial view of a building after the cable of the crane snapped on it in Manhattan, New York, May 31, 2015. Photo: Reuters/Eduardo Munoz

police New York Police Department officers attend an emergency response after the cable of the crane snapped on a building in Manhattan, New York, May 31, 2015. Photo: Reuters/Eduardo Munoz

crane Partial view of a building after the cable of the crane snapped on it in Manhattan, New York, May 31, 2015. Photo: Reuters/Eduardo Munoz

crane New York Police Department officers and Fire Department members attend an emergency response after the cable of the crane snapped on a building in Manhattan, New York, May 31, 2015. Photo: Reuters/Eduardo Munoz

crane New York Mayor Bill de Blasio (C) speaks to the media during an emergency response after the cable of the crane snapped on a building in Manhattan, New York, May 31, 2015. Photo: Reuters/Eduardo Munoz