Two firefighters — one searching for a person reported to be trapped and the other responding to a mayday call — plunged through the collapsed first floor of a burning building and died early Monday.

Rescue crews tried repeatedly to get to the two fallen firefighters, but were beaten back by fire and further collapses inside the corner brick building, Commissioner Michael Lombardo said.

The first firefighter to fall through the floor, Lt. Charles "Chip" McCarthy, was a 22-year veteran of the Buffalo Fire Department who was assigned to a team whose members are trained to find and free trapped victims.

He had depleted one oxygen tank, came out to replace it and then re-entered the building just before the accident happened, said firefighter Vincent Gugliuzza, vice president of Local 282, Buffalo Professional Firefighters Association.

He pressed a distress button on his radio and radioed for help, saying, "Basement, I'm in the basement," said Daniel Cunningham, president of the firefighters union.

Firefighter Jonathan Croom, who was working on his scheduled day off, responded to McCarthy's mayday call and also fell through the collapsed floor, Cunningham said.

Firefighters continued to search the building Monday afternoon but had not yet determined whether anyone else was still inside, officials said.

The fire at the Super Speedy deli in a working-class neighborhood on the city's east side was reported just before 4 a.m. Flag-draped stretchers carrying the bodies were brought out of the two-story building shortly before 10 a.m. as fellow firefighters, some saluting, lined up and took off their helmets. Weeping and distraught people believed to be relatives had been escorted from the scene moments earlier.

Firefighters were still pouring water on the gutted building hours after the blaze began. The fire's cause was under investigation.

McCarthy was a 45-year-old married father of three. Croom, 34, had been in the department for 10 years and leaves behind a fiance and the couple's 9-month-old child. He was working on overtime on his day off to cover a staffing shortage, Cunningham said.

The two were among the first firefighters on the scene, Lombardo said.

"The hearts of the Buffalo Fire Department are broken," said Lombardo, who knew both of the victims. "This is a family and we lost two members of our family today."

The last Buffalo firefighter killed in the line of duty was 31-year-old Michael Seguin, who died July 4, 1997, when a roof collapsed during a house fire.

The last time more than one Buffalo firefighter died in the line of duty was on Dec. 27, 1983, when five firefighters were killed in a propane tank explosion at a warehouse — the worst loss of life in the department's 129-year history.

"I've been on 36 years and seen every situation happen. We still do what we have to do," said Fire Chief John McFeely. "It's always very, very tragic. The guys are so close together, but we've got a job to do. In another half an hour, if there's another fire down the street, we'll be there."