A building burns after an explosion on 2nd Avenue on March 26, 2015 in New York City. The seven alarm fire drew firefighters from across the city. A number of injuries have been reported. (Photo by Andrew Burton/Getty Images)

UPDATED 03/27/15 12:21 a.m.

NEW YORK (CBSNewYork) – A gas explosion ripped through four buildings and ended up leveling three of them, leaving a total of 19 people injured in a bustling section of the East Village Thursday afternoon.

The explosion was reported at around 3:17 p.m. at 7th Street and Second Avenue. Fire crews were on the scene within three minutes, FDNY Commissioner Daniel Nigro said.

“It was very quick; it was very instantaneous – kaboom,” a witness told CBS2’s Valerie Castro.

A total of 19 people were injured in the blast, the FDNY said. Fourteen were civilians, and four were in critical condition. Seven suffered minor injuries, and four were treated at the scene.

Five of the injured were FDNY members. Four were hospitalized and one was treated at the scene.

The injured people were taken to Bellevue Hospital Center, Mount Sinai Beth Israel Medical Center, NewYork Presbyterian-Weill Cornell Medical Center, and Lenox Hill Hospital.

Two of the critically injured victims suffered burns to their airways, while another was unconscious following the explosion, Nigro said earlier.

“Our thoughts and prayers are with every one of them and their families. Of course, we are praying that no other individuals are injured and there are no fatalities,” Mayor Bill de Blasio said.

Whole building is in flames now. pic.twitter.com/U3zGUPqi86 — Scott Westerfeld (@ScottWesterfeld) March 26, 2015

The explosion and resulting fire tore through 119, 121, 123 and 125 Second Ave., which are mixed residential and commercial buildings, de Blasio said. The buildings at 121 and 123 both pancake collapsed, de Blasio said.

Nigro said the façade of the 121 building was blown clear across the street, 1010 WINS’ Al Jones reported.

FDNY video showed the 123 building completely collapsing to the ground.

The building at 119 Second Ave. was also left in danger of collapsing after the fire, Nigro said.

Following the blast, huge sections of the 119 building – which stood five stories high – looked like they had been punched out, WCBS 880’s Peter Haskell reported.

By 9 p.m., the 119 building was a ruin with only the front wall still standing, and looked like it could collapse, CBS2’s Tracee Carrasco reported. Only the front wall of the 121 building still stood, and the 123 building was completely leveled.

By 11 p.m., tweets from the scene showed that the 119 and 121 buildings had been completely cleared away. The 125 building remained, but sustained major fire damage.

The rest of the building next door is down. pic.twitter.com/dq62W1SeRb — Scott Westerfeld (@ScottWesterfeld) March 27, 2015

“We will be here for a very long night,” Nigro said early in the evening.

The fire quickly escalated to seven alarms after it broke out, bringing about 250 firefighters to the scene, according to the FDNY. A huge column of flame shot up 20 or more feet through the top of the building during the height of the fire.

PHOTOS: Second Avenue Building Explosion

Firefighters arrived on the scene and rushed into the inferno for rescues.

“They, for the first 15 minutes before the building started to collapse, made extremely dangerous searches of these buildings to search for any victims, and were forced out by subsequent collapse of 123 and 121,” Nigro said.