By Chris Francescani and Noreen O'Donnell
NEW YORK (Reuters) - At least 10 people were injured when part of a five-story building containing businesses and residences in Manhattan's Chinatown district collapsed after an explosion, fire officials said on Thursday.
The cause of the explosion was not immediately clear, Fire Department Assistant Chief Robert Boyce said. He would not confirm local press reports of a gas leak, saying the cause remains under investigation.
Firefighters said they responded within three minutes, arriving at 17 Pike Street at 12:45 p.m. (1645 GMT) to find part of the first floor had collapsed and the building was on fire.
Four people were seriously injured and taken to Weill Cornell Medical Center. Six others with minor injuries, including two firefighters, were taken to Bellevue Hospital, Boyce said.
Boyce said that the mixed-used building, which contains businesses on the ground floor and residential apartments above, has "existing fire code violations" that are being investigated.
A Consolidated Edison spokesman said gas had been shut off to the building after the explosion as a precaution, a routine procedure.
Witnesses said the explosion was loud, and startled neighbors and pedestrians.
"I heard 'boom'," said Yi Len, 55, a Long Island man who was visiting a local doctor when the explosion ripped through the rear of the building's ground floor, which houses a bus company office and a beauty salon. He said the explosion was followed by a strong smell of smoke for about 20 minutes.
(Corrects spelling of name in final paragraph to Yi, instead of Eyi)
(Writing by Chris Francescani; Editing by Dina Kyriakidou and James Dalgleish)