The number of pilots hit by potentially blinding laser beams rose dramatically last year, federal aviation regulators reported Wednesday.

The Federal Aviation Administration says 2,836 pilots said that they were illuminated by laser beams in 2010, nearly double the 1,527 in 2009. Reports of incidents are up tenfold since 2005, when the federal agency first began collecting laser reports.

"This is a serious safety issue," Transportation Secretary Ray LaHood says. "Lasers can distract and harm pilots who are working to get passengers safely to their destinations."

The reports came from pilots of commercial airline planes, as well as private and government aircraft.

The incidents seem most likely to occur at commercial airports in the West, the FAA reported. Four of the five airports with the most reports were in Los Angeles, Phoenix, San Jose and Las Vegas. Los Angeles International led the nation with 102 laser incidents last year.

Other busy airports around the nation, such as Chicago's O'Hare International and Philadelphia International, also experienced numerous incidents.

Pilots have reported being temporarily blinded or disoriented when light from a laser was beamed into their cockpits.

"If the vision is impaired on a pilot, it definitely puts the flight at risk," says David Zwegers, director of aviation safety at Embry-Riddle Aeronautical University in Daytona Beach, Fla. "A pilot relies on vision to orient himself. Especially with single-pilot operations, it is very, very serious. It could be lethal."

Embry-Riddle student pilots have been hit by lasers about a dozen times in recent years, Zwegers says.

Two pilots for the Collier County Sheriff's Office in Florida were temporarily grounded for several days after their helicopter was illuminated by a green laser early New Year's Day as it flew over Naples, Fla. Two teenagers were arrested and charged in the incident.

A review of National Transportation Safety Board accidents and incidents did not reveal any since 2000 that were linked to lasers.

Still, the issue has become an increasing concern among pilots as the incidents have grown rapidly. The FAA attributed the increase to several factors. Improvements in laser technology have meant that powerful units that can hit aircraft at higher altitudes are far less expensive than just a few years ago. The agency also thinks that more pilots are reporting the incidents than in previous years.

"The FAA is actively warning people not to point high-powered lasers at aircraft because they can damage a pilot's eyes or cause temporary blindness," FAA Administrator Randy Babbitt says. "We continue to ask pilots to immediately report laser events to air traffic controllers so we can contact local law enforcement officials."