NEW YORK (AP) — Firefighters are working to put out pockets of fire at the site of a blaze that leveled an apartment building in Manhattan's East Village.

A fire department spokesman says about 200 firefighters and medical staff are on the scene Friday morning.

He says large volumes of water are being poured over the rubble.

Because the building collapsed he says it could take days to bring the fire under control.

Nineteen people were injured, four critically after an apparent gas explosion sent flames soaring and debris flying on Thursday.

Preliminary evidence suggested a gas explosion amid plumbing and gas work inside the building was to blame.

The spokesman says the operation is currently in "the extinguishing phase" — making sure there are no further fires and putting out the fires still there.