WASHINGTON (AP) _ The Federal Aviation Administration said today it is aware of tiny new guns that look as harmless as a key chain and has taken appropriate security measures to ensure they do not get on airplanes.

The $20 gun is 3 inches long and an inch wide, but it can fire two .32-caliber bullets and would be deadly from 20 yards away. The weapon is cocked by pulling on the ring and fired with the push of a button.

``It doesn't look like a weapon. If you showed it to airport security, they would probably think it's a key ring,'' Brian Hurrell, director of customs in Perth, Australia, told The New York Times, which first reported about the gun.

The FAA, which is charged with U.S. aviation security, said it was warned about the gun earlier this year by Greek officials and has since warned all airlines and airport managers.

``Beyond that, we can't discuss our security arrangements at any of our facilities, because that would serve as a guide for the terrorists,'' said FAA spokeswoman Rebecca Trexler.

Asked if she was confident the weapon can be detected, Trexler replied: ``All I can say is that we have appropriate security measures in place and everyone is aware of this weapon.''

She said there were no changes planned in the public's check-in routine at airports.

The guns, which are widely available in southern Europe, have turned up at airports in Australia, England and Greece since September. An Interpol official told the Times the gun is apparently made in Bulgaria.

An instruction book found with the gun in Australia described the weapon as an ``OSA double-loader gas-signaling device for self-defense.''