The Homeland Security Department, citing "credible" intelligence about a possible new threat, issued a warning about explosives hidden in shoes on Wednesday. That warning should sound familiar: ever since Richard Reid tried and failed to detonate explosives hidden in his shoes onboard a plane, airline passengers have removed their shoes during security screenings in the U.S. The new potential threat was first reported by NBC News. 

As a result, airlines will likely pay a lot more attention to the shoes on passengers (and in their luggage) for the near future. That's just as the TSA seemed to be getting ready to relax some screening restrictions, more than a decade after the U.S. stepped up its security screenings in response to the September 11, 2001 terrorist attacks. In September of last year, the TSA announced that it would expand its accelerated "PreCheck" screening program to more airports. The program allows certain approved passengers to bypass most security checks. 

While officials described the threat as "moderate, " it will have a definite impact on travelers, some more than others. Here's more, from NBC: 

Airlines will be playing extra attention to passenger shoes on flights to the US from overseas. Those passengers may also experience increased scrutiny in pat downs and full-body screening.The bulletin to airlines urges screeners to use the explosive trace detection swabs to check shoes that are worn and in carry-on bags. The officials say the threat information was not specific to any particular airline, country, or time.

Coincidentally, one of the men convicted for the 2001 failed shoe bomb plot that led to the screening restriction in the first place was requested for testimony this week for the trial of a separate terrorism case.