NEW YORK >> Rescuers working amid gusty winds, cold temperatures and billowing smoke pulled four additional bodies overnight from the rubble of two Manhattan apartment buildings, as the death toll rose Thursday to at least seven from a gas leak-triggered explosion that reduced the area to a pile of smashed bricks, splinters and mangled metal.

The explosion Wednesday morning in East Harlem injured more than 60 people, with searchers still trying to locate others a day later. Crews used generator-powered floodlights and thermal imaging cameras to identify heat spots — bodies or pockets of fire — at the site on Park Avenue and 116th Street. Police guarding the scene wore surgical masks and neighborhood residents covered faces with scarfs amid the thick, acrid air.

"This is a difficult job, a challenging job," Fire Department spokesman Jim Long said. He said it was "a very terrible and traumatic scene."

Searches of the street were completed Wednesday evening and no victims had been found there, city officials said. Workers initially were hampered from fully accessing the building space because of a sinkhole caused by a subsurface water main break. The weather also posed a challenge, with temperatures dropping into the 20s and rain falling, but workers remained at the site.

The fiery blast erupted at about 9:30 a.m., around 15 minutes after a neighboring resident reported smelling gas, authorities said. The Con Edison utility said it immediately sent workers to check out the report, but they didn’t arrive until it was too late.

The explosion shattered windows a block away, rained debris onto elevated commuter railroad tracks close by, cast a plume of smoke over the skyline and sent people running into the streets.

"It felt like an earthquake had rattled my whole building," said Waldemar Infante, a porter who was working in a basement nearby. "There were glass shards everywhere on the ground, and all the stores had their windows blown out."

Hunter College identified one victim as Griselde Camacho, a security officer who worked at the Silberman School of Social Work building. Hunter, in a statement on its website, said Comacho, 45, had worked for the college since 2008.

Also killed was Carmen Tanco, 67, a dental hygienist. Her cousin News 12 cameraman Angel Vargas said the family started a frantic search when she didn’t show up for work Wednesday.

New York police identified another victim as Rosaura Hernandez Barrios, 21.

The bodies of three unidentified people also were found. A man was pulled from the rubble just after midnight Wednesday, a woman found at about 2:50 a.m. Thursday and a man discovered about a half-hour later. The seventh victim, recovered around 7:15 a.m., was an adult male, police said.

At least three of the injured were children; one, a 15-year-old boy, was reported in critical condition with burns, broken bones and internal injuries. Most of the other victims’ injuries were minor and included cuts and scrapes.

A tenant in one of the destroyed buildings, Ruben Borrero, said residents had complained to the landlord about smelling gas as recently as Tuesday.

A few weeks ago, Borrero said, city fire officials were called about the odor, which he said was so bad that a tenant on the top floor broke open the door to the roof for ventilation.

"It was unbearable," said Borrero, who lived in a second-floor apartment with his mother and sister, who were away at the time of the explosion. "You walk in the front door and you want to turn around and walk directly out."

The fire department said a check of its records found no instances in the past month in which tenants of the two buildings reported gas odors or leaks.

Jennifer Salas lived in one of the buildings. She told The New York Times that her husband, Jordy Salas, and their dog were in the building at the time of the collapse and were missing.

"There’s six floors in the building; each floor has one apartment," she said. "Last night it smelled like gas, but then the smell vanished and we all went to sleep."

Salas’ family continued to hold out hope Thursday that he’d be found alive.

His father-in-law, Jorge Ortega, told The Associated Press that the 21-year-old was last seen Wednesday morning when he returned from his night job at a Bronx restaurant.

Ortega said his distraught daughter, who is six months pregnant and whom he identified as Jennifer Mendoza, went to the hospital Wednesday but was resting at his home on Thursday.

Ortega said Jordy Salas’ father was up all night waiting for any news.

Edward Foppiano, a Con Ed senior vice president, said there was only one gas odor complaint on record with the utility from either address, and it was last May, at the building next door to Borrero’s. It was a small leak in customer piping and was fixed, he said.

The block was last checked on Feb. 28 as part of a regular leak survey, and no problems were detected, Foppiano said.

One of the side-by-side buildings had a piano store on the first floor, the other a storefront church.

City records show that the building Borrero lived in was owned by Kaoru Muramatsu, proprietor of the piano business. A phone number listed for Muramatsu rang unanswered.

Records at the Department of Housing Preservation and Development indicate the agency responded to complaints from a tenant and cited Muramatsu in January for a broken outlet, broken plaster, bars over a fire escape, a missing window guard and missing carbon monoxide and smoke detectors.

City building records don’t show any work in progress at either address, but the building owned by the Spanish Christian Church had obtained permits and installed 120 feet of gas pipe last June.

Con Ed said it remains to be seen whether the leak was in a company main or in customer-installed inside plumbing. The gas main that serves the area was made of plastic and cast iron, and the iron dated to 1887, Foppiano said.

"Age is not in and of itself an issue with cast iron," he said, noting that Con Edison has a cast iron replacement program and the pipe was not slated to be removed in the next three-year period.

A National Transportation Safety Board team arrived in the evening to investigate. The agency investigates pipeline accidents in addition to transportation disasters.

NTSB team member Robert Sumwalt said investigators would be looking at how Con Edison handles reports of gas odors and issues with the pipe and would be constructing a timeline of events.

Just before the explosion, a resident from a building next to the two that were destroyed reported smelling gas inside his apartment and thought the odor might be coming from outside, Con Ed spokesman Bob McGee said.

On Wednesday night, the American Red Cross served meals to more than 130 people living in seven buildings impacted by the blast. The Salvation Army provided accommodations in one of its shelters.

The explosion destroyed everything Borrero’s family owned, including the ashes of his father, who died a few years ago. Borrero said he assumes his 5-year-old terrier, Nina, was killed.

But "I have my mother and sister," he said. "I’m happy for that."

Associated Press writers Julie Walker, Verena Dobnik, David B. Caruso, David Crary, Leanne Italie, Meghan Barr and Mike Casey contributed to this report.