A utilities company reportedly had been called to the scene to check on a gas leak.
NEW YORK — A massive explosion believed to be due to leaking gas leveled two East Harlem apartment buildings Wednesday, killing two people, injuring nearly two dozen and triggering a search for other possible victims still missing.
Two women were killed, and New York City Fire officials said at least 22 people were hurt, two of them with life-threatening injuries.
The department said more than a dozen people were still missing, and rescuers picked through smoldering rubble looking for any victims.
Mayor Bill de Blasio, speaking with reporters, said finding them is a top priority but cautioned that many may have fled to safety.
Standing outside a scene of twisted, smoking devastation, de Blasio said preliminary indications point to leaking gas as a cause.
"This is a tragedy of the worst kind because there was no indication in time to save people," de Blasio said. "We have lost two people already."
Some 200 firefighters worked to control the fire that followed the blast.
Raphael Ruiz-Moran stood outside with other onlookers waiting to get what information he could. His uncle and other family members live about half a block from the scene and so far, he got no answer when he tried to call them.
The buildings, now flattened, housed a Spanish Christian Church and a piano repair store at the East Harlem address on Park Avenue between 114th and 116th streets.
"It felt like an earthquake had rattled my whole building," Waldemar Infante, a porter who was working in a basement nearby, told the Associated Press. "There were glass shards everywhere on the ground, and all the stores had their windows blown out."
The mayor said the explosion occurred at 9:31 a.m. ET, only minutes before a Con Ed utilities team arrived on the scene to check on reports of a natural gas leak.
Elhadj Sylla said he was about a block away at around 8:45 a.m. when he noticed a faint smell of gas.
Not long after, he rushed outside after hearing a tremendous explosion, but was unable to see anything through the thick air.
"It was very dark," said Sylla, 54. "There was smoke, dust. I thought maybe the train was coming down," he said, referring to the Metro-North commuter railroad elevated tracks across the street on Park Avenue.
"I thought it was the end of the world," he said. "I thought my life was ending."
As residents gathered near the scene, white smoke still billowed up from the debris in waves and left a chalky taste in the air.
Ruiz-Moran, who lives a block from the scene and ran outside when he heard the blast, said he got within half a block of the building.
"I saw the people on the ground " said Ruiz-Moran, 38. "They had cuts. There was glass."
About two minutes after the initial blast, Ruiz-Moran said, he saw a burst of fire, which lasted a couple of minutes.
Desiree Thompson was walking along Park Avenue with a friend across the street when the explosion occurred.
"We heard this loud bang and the glass flew by us," said Thompson, 58. "My eardrums closed. I thought the train had crashed," she said, referring to the Metro-North commuter train.
The windows blew out of a nearby, she said. "I started screaming and crying."
Normally, Thompson walks on the side of the street from the apartment buildings, but for no particular reason decided to walk on the other side of the street this morning. "If I had been over there, I would be dead," she said.
Anthony Saunders, who lives nearby, said, "The doors rattled, the windows rattled." He said he rushed to the scene, which was filled with an acidic smell like burning rubber.
Saunders said building was older, likely full of plywood and plaster. "It's a 100-year-old building," he said. "It's pretty much kindling."
The Metro-North service into and out of Grand Central Terminal was suspended because of debris on the elevated train tracks.
Ken Gray, who commutes into the city from Montgomery, N.Y., estimates that he just missed the blast this morning as his train headed into Grand Central Station.
"I'm alive and didn't get hurt and that's what counts," he said. "We have to pray for the people who were hurt and killed."
Stanglin reported from McLean, Va. Contributing: USA TODAY's William M. Welch in Los Angeles; Ken Valenti, The (Westchester, N.Y.) Journal News