hotographs posted on social media by witnesses showed thick black smoke billowing around the area.
Shameem Noor, a cashier at a restaurant nearby, said: "We heard a big sound, then three or four people fell on the street. People were running and scared. There's a big fire on the roof and black smoke."
According to the New York Post sources suggested as many as 30 people were hurt in the incident which happened ta 3.30pm local time.
One witness said on Twitter: "Just heard an explosion and my entire building shook." Another said: “All of Greenwich Village smells like smoke."
The New York Daily News reported half a dozen people were being treated at the scene and two firefighters were injured
A Fire Service spokesman said: "This is being considered a major emergency."
In March 2014, eight people were killed when a gas explosion leveled two apartment buildings in Harlem in northern Manhattan.
A New York Fire Department spokesman told the New York Times, initial indications were that there had been a gas explosion.
He said: "It was probably a gas thing, it looks like, but that’s not confirmed.