US airports on alert after al-Qaida posts 'hidden bomb' instructions online

CHICAGO (WLS) -- U.S. airports are on alert after a new call to action from al-Qaida.

The terror group published instructions online that explained how to build a bomb with no metal parts, which could slip past standard airport security equipment.

Bomb experts called the step-by-step directions on making a so-called "hidden bomb" are lethal and very detailed. The instructions even include where to sit on the plane to maximize damage.

But what's most alarming to U.S. security officials is that the device would only be detected by full body scanner machines, which many smaller airports don't have.

Many travelers at O'Hare International Airport had not heard of the "hidden bomb" before they arrived Wednesday morning.

"I think the airports can screen people correctly. I think, especially at O'Hare, things will go smoothly," Theresa Love said.

"We're always going to have threats. But to live in fear just isn't worth it. They're always going to come and go. We can't really worry about that. If you do, it's going to end up ruining your day or your trip," said David Welter, a passenger.

"I think these kinds of things are really awful when they happen. We feel secure because we are going to Mexico and we know maybe it's not a place where things like this can happen," said Natalia Resmini, another traveler.

TSA screeners are already under orders to ramp up the number of random searches, both on passengers and carry-on luggage. Those orders were prompted by the terror attacks in France last week.

The Department of Homeland Security asked the TSA to do a short-term review, to determine if more security measures are needed at O'Hare.