Allentown, Pennsylvania (CNN) -- The death toll in a suspected natural gas explosion that destroyed eight homes in Allentown, Pennsylvania, rose to five Thursday evening, authorities said. The victims include a 4-month-old and a 79-year-old.

Authorities sifted through piles of rubble on a snowy street.

Allentown Fire Chief Robert Scheirer confirmed four of the deaths. Scott Grim of the Lehigh County Office or the Coroner confirmed the fifth.

"It was a difficult fire to fight because of the weather," said Scheirer, noting that the icy conditions were made worse as firefighters pumped water into a blaze that burned down houses and spewed out of street gas lines.

"I believe we're dealing with a recovery at this point," he told CNN earlier. "The fire is out; the gas line has been shut off. We have all the shelter victims being returned to their homes -- the homes that can be habitable at this point."

Backhoes and other heavy equipment could be seen assisting authorities as they searched the rubble.

The blast was reported just before 11 p.m. Wednesday, authorities said.

A pair of homes were flattened and burning after the initial explosion, and six more were consumed by the resulting fire, according to the fire chief. Another 16 homes were affected by the blast, he said.

Antonio Arroyo, 43, and his wife, Jill, were renting one of the homes that burned. He lived seven houses down from where the blast took place.

He told CNN he was on the computer when the explosion occurred, but had turned away to speak to his wife.

"When the explosion hit, the flat screen on my desk slaps me on the back," he said. Arroyo said he turned around to find that everything had been knocked off the desk, and the home's windows had been "pushed in."

He said the blast sounded like a bomb -- not a gunshot or fireworks -- and he thought war had been brought "to our doorstep. ... This was one huge vibration that shot through the neighborhood. I started looking at the sky, looking at the ground, to see what I was looking for."

He said his wife told him a car was on fire outside, and he ran out to see if he could help.

"I was shocked," he said. "The whole house was missing. The whole house at the end of the block was missing. There was nothing but flames."

Police told them to leave their home, he said, and he left everything behind. He recalled watching the fire "go from roof to roof to roof. One volunteer said, 'It doesn't look good.'"

"We got to start all over again," he said. "It's just stuff. We should be able to jump back from this."

The cause of the explosion wasn't immediately known, but Scheirer said utility crews came to the scene and shut off a gas line that was fueling the flames.

"We don't have anything confirmed yet at this point," Scheirer said when asked about the cause of the blast. "We believe it to be a natural gas explosion. We don't know if the leak was inside the home or out on the street. That all has to be investigated."

In winter, he said, "Gas lines are like water lines. As the ground freezes and thaws, you know, it tends to shift. And sometimes it cracks the pipes ... the cause of gas leaks and water leaks.

"If gas is leaking out into the street, you know, it's going to follow the path of least resistance and it could seep in the ground, into your home and stuff," Scheirer said. "And any ignition source inside the home could create that explosion."

The blast occurred a short distance from the Gross Towers senior center, which was evacuated. About 500 people were in shelters immediately after the explosion. They were returned to the center Thursday, Scheirer said.

"It's very cold. I was very concerned with my firefighters getting frostbite last night. We set up tents and stuff to try to keep them warm. We were relieving them as rapidly as we could. (It's) very difficult with the amount of snow that we've had here in the city lately. ... And of course, once we start throwing water, everything turns to ice."

In September, a natural gas pipeline explosion in San Bruno, California, killed eight people. The explosion and the resulting fire injured 52 people and destroyed 37 homes. The blast sent a 28-foot section of the gas pipeline 100 feet into the air and blew in the doors of a grocery story a quarter-mile away.

Last month, a gas main explosion in Philadelphia killed a utilities worker and injured five other people.