A laser beam aimed at a Chicago-bound jet may have been a prank, FBI (search) officials said Monday, adding that terrorism has been ruled out.

The flight crew of a United Airlines flight to O'Hare International Airport from Nashville reported seeing a green laser beam Sunday night shortly after the plane took off, said Lynne Lowrance of the Nashville International Airport (search).

The flight, which had about 30 people on board, landed safely in Chicago. The airport property was canvassed and nothing suspicious was found.

"We know that there wasn't any terrorism involved and it possibly could have been someone playing a prank," said Doug Riggins of the FBI's Joint Terrorism Task Force.

The Transportation Security Administration (search) and the Federal Aviation Administration, which are also investigating, declined to give further details.

Federal agents are looking into similar incidents involving lasers and aircraft, including cases in Cleveland; Washington, D.C.; Houston; Colorado Springs, Colo.; Medford, Ore.; and Teterboro, N.J.

Laser beams can temporarily blind or disorient pilots and possibly cause a plane to crash. Federal law enforcement officials have said they've found no evidence of a terrorist plot involving the laser beams.