WASHINGTON (AP) -- Airlines are being warned by the government that terrorists are considering surgically hiding bombs inside humans to evade airport security. As a result, travelers may find themselves subjected to more scrutiny when flying in the heart of summer vacation season, especially to the U.S. from abroad.

The FBI and Homeland Security Department sent a memo to security officials around the country on Wednesday about "body packing," describing it as a "criminal tactic with possible terrorist application."

The memo, obtained by The Associated Press, cited a 2005 incident in which Colombian men were accused of surgically implanting narcotics into human couriers.

The memo offered possible indicators of surgically implanted contraband, including a distended stomach or other unusual bulging, and visible physical discomfort from a pat-down.

Bombs-in-the-body is not a new idea, but recent intelligence indicates a fresh interest in using this method. People-scanning machines in airports aren't able to detect explosives hidden inside humans. Still, there is no current information that points to a specific plot involving surgically implanted explosives, a U.S. security official said, speaking on condition of anonymity to discuss such sensitive matters.

As airport security has increased since the Sept. 11, 2001, terror attacks, so has the terrorists' creativity in developing methods to get around it. Aviation continues to be a special target, and evidence from Osama bin Laden's compound showed that the al-Qaida leader retained his fascination with attacking airplanes until his death in May.

Last year, it was reported that British officials uncovered intelligence that al-Qaida was seeking to surgically implant bombs inside people, a move some believed was prompted by the use of full-body imaging machines at major airports around the world.