Four firefighters were killed while battling a fire that engulfed a Houston motel and restaurant on Friday, and at least five other people were hospitalized, authorities said.

Flames were shooting from the roof of the Southwest Inn, along one of Houston's most heavily traveled expressways, and black smoke was blanketing the area as firefighters tried to extinguish the blaze.

Three firefighters were killed at the scene, while the fourth died at a hospital, according to the mayor's office and local medical examiner. Five other people were injured and were being treated at a hospital for chest pains or leg injuries.

The loss of life is the single worst in the history of the 116-year-old Houston Fire Department. When a flag-draped body was removed from the smoldering remains around 4 p.m., firefighters _ working in swirling winds and temperatures exceeding 90 degrees Fahrenheit (32 Celsius)_ paused and saluted.

``It's a very sad day for the Houston Fire Department and the city of Houston as a whole,'' said Janice Evans, a spokeswoman for Houston Mayor Annise Parker.

Field reports indicate that the firefighters were caught in a roof collapse, said Jeff Caynon, president of the Houston Professional Fire Fighters Association.

Caynon said the victims included three men and one woman. Their names haven't been released.

The blaze broke out just after noon Friday at a restaurant and club at the motel, then quickly spread to the section of the building housing the motel.  About 150 firefighters responded and were able to extinguish the blaze within about two hours.

Front desk clerk Martha Lopez told the Houston Chronicle that a restaurant employee ran into the hotel saying a fire had started in the restaurant. The two began knocking on doors and windows telling guests to get out of the hotel. Lopez said the hotel could accommodate 100 guests and had 45 registered at the time of the fire. (AP)