At least three crude bombs exploded and two others were disarmed Friday at the homes of people who work for an FAA contractor in Grand Junction, prompting evacuation of the air traffic control tower at the city airport, officials said.

No injuries were reported and there were no delays at the airport.

The bombs were placed at homes of people who work for Serco Group Plc., which operates Grand Junction's air traffic control tower, said Steve Christmas, the company's vice president for aviation operations. Police asked residents to help them find a former employee they described as a "person of interest."

Denver controllers handled air traffic for Grand Junction for about an hour until controllers were able to return to the tower there, FAA spokeswoman Laura Brown said. A security sweep was being conducted at Walker Field Airport, said Carrie Harmon, a spokeswoman for the Transportation Security Administration.

The bombs had "no known link to aviation," Harmon said, and the sweep was conducted "out of an abundance of caution."

Grand Junction police Sgt. Paul Quimby said the devices resembled incendiary devices rather than bombs; one explosion scorched the front of a garage door and melted the vinyl siding.

Quimby declined to comment on a report in the Daily Sentinel of Grand Junction that the bombs were contained in black, office-style trash cans covered in silver duct tape, but said they could have been made "by kids with the Internet and a little ingenuity."

Police asked residents to help them find Robert L. Burke, 54, who Christmas confirmed was a former Serco employee. Police described him as a person of interest rather than a suspect, but would not elaborate.

The bombs prompted warnings from authorities as they fanned out across this western Colorado city of 45,000 looking for suspects and more devices.

"It could have killed my family," said Richard Smith, whose house received minor damage. "It was a little scary but it happened at 4:30 in the morning" and everyone was inside.

Christmas said his company was offering assistance to the affected employees, including offering them the opportunity to spend the night somewhere else.

A team from the federal Bureau of Alcohol, Tobacco, Firearms and Explosives was heading to the scene, ATF spokeswoman Sheree Mixell said.

Serco, a British company, operates 54 air traffic control towers for the FAA, according to its Web site.