The FBI announced Friday it has assigned its Joint Terrorism Task Force to lead a probe of laser attacks on the cockpits of two planes approaching LaGuardia Airport this week, inviting help from the public as well to fight a growing threat against the nation’s air transportation.

The FBI is looking for the pranksters behind a couple of laser pointer incidents at LaGuardia Airport on Tuesday.

NEW YORK — The FBI announced Friday it has assigned its Joint Terrorism Task Force to lead a probe of laser attacks on the cockpits of two planes approaching LaGuardia Airport this week, inviting help from the public as well to fight a growing threat against the nation’s air transportation.

“The FBI is asking anyone with information about any of these dangerous laser incidents to pick up the phone and call us,” George Venizelos, head of the FBI’s New York office, said in a release. “Our paramount concern is the safety of aircraft passengers and crew.”

The announcement came along with a report that laser attacks against inbound flights at New York airports have increased 17 percent so far this year, a rising threat because lasers can temporarily or permanently blind a pilot and crew, the FBI said.

The FBI said Friday a reward is available for anyone providing information leading to arrests in the Tuesday evening attacks.

The FBI said the first attack occurred when a Shuttle America cockpit was illuminated by a green laser on its final approach to LaGuardia at 7:35 p.m. Tuesday. The FBI said the crew reported that the laser appeared to originate about a half mile west of the New York Botanical Garden in the Bronx, striking the plane when it was 2,000 feet above ground, about six miles from the runway.

The second incident occurred three hours later when a private aircraft reported a green laser two miles southwest of LaGuardia at 10:37 p.m. as it headed eastbound over the Triborough Bridge. The FBI said the laser originated near the intersection of Broadway and Steinway Street in Queens.

No injuries were reported in either incident, though the FBI noted that several commercial pilots earlier this year suffered significant injuries including a burnt retina.

The probe is being led by the FBI’s Joint Terrorism Task Force, which includes more than 50 local, state and federal agencies.

The Federal Aviation Administration announced two years ago that it would fine those who point lasers at planes up to $11,000 per violation after reports of people shining hand-held lasers at planes soared, rising from a few hundred instances of laser attacks on planes in 2005 to nearly 3,000 reports in 2010.

The lasers, marketed as tools to point out stars at night, are much more powerful than laser pointers used by lecturers. They can be seen up to 25,000 feet away and are used by bird watchers, astronomers and lecturers to point out faraway objects.

In 2009, a Southern California man was sentenced to 2½ years in a federal prison after he became the first person in the nation convicted at trial of interfering with pilots by aiming lasers at their planes. He had aimed a hand-held laser at two Boeing jets as they were landing in May 2008.

In 2005, a New Jersey man was arrested and charged under the Patriot Act for aiming a green laser at a small jet flying over his home near Teterboro Airport a year earlier. The man, who was eventually sentenced to probation, said he had been using the device to point at the stars from his backyard.