Four Houston firefighters died Friday while responding to a massive 5-alarm fire at a motel, a city official told FoxNews.com.
It is not immediately clear if the firefighters died at the scene, but the city official said five additional firefighters are being treated at area hospitals. 
MyFoxHouston.com reported that over 100 firefighters battled the blaze in sweltering temperatures. 
The fire broke out just after noon Friday at a restaurant and club at the Southwest Inn on U.S. 59, one of Houston's most heavily traveled expressways. Flames spread to the motel part of the building and were still shooting from the roof of the structure more than an hour later.
No cause for the blaze was immediately announced. Phone messages left with the fire department weren't immediately returned.
Temperatures in the low 90s and high humidity hampered firefighting efforts, and smoke from the fire snarled traffic on the expressway.
Fox News' Edmund DeMarche contributed to this report