The TSA has notified airports to be on the lookout for terrorist “dry runs,” and they have good reason to be worried, after numerous suspicious incidents: Airports warned about terror dry runs.

WASHINGTON - Airport security officers around the nation have been alerted by federal officials to look out for terrorists practicing to carry explosive components onto aircraft, based on four curious seizures at airports since last September.

The unclassified alert was distributed on July 20 by the Transportation Security Administration to federal air marshals, its own transportation security officers and other law enforcement agencies.

The seizures at airports in San Diego, Milwaukee, Houston and Baltimore included “wires, switches, pipes or tubes, cell phone components and dense clay-like substances,” including block cheese, the bulletin said. “The unusual nature and increase in number of these improvised items raise concern.”

Security officers were urged to keep an eye out for “ordinary items that look like improvised explosive device components.”

The 13-paragraph bulletin was posted on the Internet by NBC Nightly News, which first reported the story. A federal official familiar with the document confirmed the authenticity of the NBC posting but declined to be identified by name because it has not been officially released.

“There is no credible, specific threat here,” TSA spokeswoman Ellen Howe said Tuesday. “Don’t panic. We do these things all the time.”

So they noticed four of these rehearsals. How many incidents did the geniuses of the TSA fail to notice? We have no way of knowing, of course.

Don’t panic. This happens all the time. Just roll over, and go back to sleep.

(Hat tip: cbinflux.)

UPDATE at 7/24/07 9:44:39 pm:

I give you, the geniuses of the TSA: Gap in security at Sky Harbor.

The federal security director at Sky Harbor International Airport was placed on leave Monday and screening was stepped up after reports of a security gap at the nation’s ninth-busiest airport.

Paul Armes was suspended after Channel 15 (KNXV, an ABC affiliate) aired videotape of Sky Harbor employees entering secured areas without having their bags screened by private guards, metal detectors or X-ray machines. Workers breezed through checkpoints with suitcases, backpacks, a cart of newspapers and even a bicycle.

(Hat tip: bosforus.)