Two firefighters died Monday after a burning building on Independence Avenue in Kansas City collapsed on them, officials said, according to reports. The firefighters were not immediately identified and officials added that two other firefighters were injured in the accident.

Fire officials were sent to the scene at about 7:30 p.m. and saw that the structure was heavily damaged in the fire. The crew evacuated people from the building, which included apartments, and just before the structure’s collapse, fire officials on ladders had rescued two people. A report by Kansas City Star said that the firefighters were evacuating people from a section of the building that had partially collapsed, when a further collapse injured four people, two of whom died.

“This is the worst day,” Kansas City Fire Chief Paul Berardi said, according to Kanasas City Star, adding: “It’s difficult when you’re with somebody 24 hours a day and laughing and joking and then something like this happens.”

Lawrence Ray Lee, a resident of the building, who was at home when the fire started, said, according to Kansas City Star, that this is the second fire in the building in the year that he lived there. “I was laying down and heard somebody yell, ‘Everybody get out,’ ” Lee reportedly said, adding: “I opened my door and there was smoke really bad.”

Officials reportedly said that one of the injured persons will be released from hospital Monday night while another was expected to be released Tuesday. It was not clear what started the fire.

“It’s going to be a difficult month,” Berardi said, according to Kansas City Star, adding: “I know Kansas City, and I know Kansas Citians will be reaching out to the Fire Department to help. There will be a time for that.”

Fire officials said that they had last seen such an incident in 1988 when an explosion at a construction site killed six firemen.

"Tonight's tragic loss is a reminder that Kansas City firefighters put their lives on the line for all of us every day," Mayor Sly James said in a statement, according to the Associated Press, adding: "Our condolences go out to the loved ones of those who made the ultimate sacrifice today, and we pray for recovery of the injured."