NEW YORK -- Crews using thermal imaging cameras in the rubble of two collapsed apartment buildings in East Harlem found four more bodies overnight Thursday, bringing to seven the death toll from an apparent gas leak explosion.
At least 60 people, including three children, were hurt in the blast that leveled the five-story buildings on Park Avenue and 116th Street.
Officials said a half dozen people are still unaccounted for at the site, which housed a Spanish Christian church and a piano repair store.
Police guarding the scene, which was lit with powerful floodlights during the night, wore surgical masks. Neighborhood residents covered faces with scarfs amid the thick, acrid air.
The imaging machines were brought in to spot heat signatures from bodies and pockets of smoldering fire.
"This is a difficult job, a challenging job," Fire Department spokesman Jim Long said. He said it was "a very terrible and traumatic scene."
Police said the dead included two women in their 40s. Among them was Griselde Camacho, a security officer who had worked for Hunter College since 2008.
Mayor Bill de Blasio, speaking to reporters at the scene Wednesday, said the explosion erupted only minutes before a Con Ed utility crew arrived to check 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."
Desiree Thompson was across the street with a friend when the blast erupted.
"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.
Thompson said she usually walks in front of the apartment buildings every morning, but on Wednesday, for no particular reason, decided to walk on the other side of the street. "If I had been over there, I would be dead," she said.
Contributing: Associated Press