HOUSTON -- Flames devoured a small cluster of townhomes in northwest Houston on Saturday, KPRC Local 2 reported.

The blaze broke out on Utah Street near Washington Street shortly before 6 a.m.

Residents managed to scramble to safety, but a firefighter and police officer were hurt as crews struggled to get the three-alarm blaze under control.

"We could actually see it when we left the station, so it was a fast-developing fire," Houston Fire Department District Chief T.J. Slagle said. "You can see the volume of fire they had, so they were taking a beating when they got in there."

By the time firefighters arrived, smoke blanketed the neighborhood and flames had already destroyed two partially built townhomes. Firefighters were then faced with the crucial task of stopping the flames from spreading to nearby buildings, which were already taking damage.

"When they're under construction there's no sheetrock. There's really nothing to slow that fire spread down," Slagle said.

A Houston police officer was hurt when a powerful stream of water from a fire department ladder truck knocked him down and a Houston firefighter fell and hurt his elbow.

Arson investigators do not yet know what started this fire, but they said they think it started in a construction dumpster that was used to collect debris from the units, which were still under construction.

"We're trying to figure what's going on, what happened to the house and the damages," home builder Ali Samie said.

Samie said while his home escaped the worst of the flames, the damage from the fire set him back at least a month from finishing construction.

"Cleaning it out is one part. Then taking all of this stuff back out and put it back in," Samie said.

In all, the fire destroyed two townhomes and damaged six more.

"There's some broken windows, minor smoke and water damage, but structurally they'll be repairable," Slagle said.