The New York City Fire Department reported a "major building collapse" and a seven-alarm fire in Manhattan's East Village on Thursday afternoon.
Four buildings on Second Avenue between Seventh Street and St. Marks Place were affected by the incident, according to officials. Local media reports suggested an explosion occurred in a restaurant near the ground floor of the building, and fire spread to apartments on the upper floors.
A FDNY spokesman said that 19 people were injured in the explosion and resulting collapse, with four of those individuals in critical condition, but there are no reports of anyone missing. New York Mayor Bill de Blasio said at a news conference just after 5:30 p.m. ET that there had not been any reports of additional missing individuals.
De Blasio said the original blast appeared to have occurred at 121 2nd Ave., and that a preliminary investigation suggested that it was a "gas-related explosion" caused by plumbing and gas work in the building.
He said that 119, 123 and 125 2nd Ave. were also affected by the explosion—and that 123 had also collapsed.
The mayor said that early reports indicated Consolidated Edison workers had been at 121 2nd Ave. before the explosion, inspecting private contractor work.
Local media reported that gas to the building was supposed to have been shut off while the contractor work occurred in 121 2nd Ave.
The FDNY told CNBC just after 4:10 p.m. ET that one building had totally collapsed and two more remained on fire. Before the apparent collapse, local media broadcasts showed thick plumes of smoke and fire spewing out of a building's windows and roof.
People could be seen being carried on stretchers from the brick structure that was ablaze.
Reports of the incident came in around 3:17 p.m., according to the FDNY. The department told CNBC it had more than 200 personnel on the scene.
New York's fire commissioner said that firefighters had made "extremely dangerous" searches of the nearby buildings before the collapse occurred.
The department told WNBC following the building collapse that it could account for all of its personnel.
Residents said the ground floor of the building where the explosion occurred housed a sushi restaurant. It is located in Manhattan's East Village, a neighborhood of small businesses, restaurants and apartments. The five-story building had 26 apartments and was built in 1900, according to online real estate sites.
"We heard a big sound, then three or four people fell on the street," said Shameem Noor, a cashier at Veselka, a restaurant about a block away.
"People were running and screaming," he said. "There's a big fire on the roof and black smoke."
Jessie Ballan owner of Café Mocha, a nearby business, told CNBC the police had ordered him to close his business due to too much smoke.
Mark Sydorak, a 70-year-old accountant who works nearby, said he rushed outside when he heard a loud explosion.
"I just heard a big boom," said Sydorak. "Then a whole bunch of smoke came out and there was a huge fire."
Consolidated Edison told CNBC around 4:20 p.m. that its crews were on location and had begun shutting down area gas service. Local media reported that the gas had still not been shut off by 5:50 p.m.
The American Red Cross told CNBC that it had sent units to the scene. The New York City Police Department said in a tweet that a displacement shelter had been set up at PS 63 located at 121 East 3rd St.
In a 4:58 p.m. ET tweet, Uber said that it would make all rides from the East Village area free of charge.
There were some reports that smoke from the incident could be smelled in midtown.
Hundreds of onlookers had gathered to watch from behind police barricades, and dozens of emergency vehicles were on the scene. Traffic in lower Manhattan had reportedly crawled to a virtual standstill.
As of 5:30 p.m. ET, the NYPD had closed Second Avenue between Houston Street and 14th Street.
—CNBC's Fred Imbert, Reuters and The Associated Press contributed to this report.