Updated

The implementation of tighter cellphone security at overseas airports could spell big hassles for travelers to the U.S.

Last week Secretary of Homeland Security Jeh Johnson directed the Transportation Security Administration to implement enhanced security at certain foreign airports operating direct flights to the U.S. In a statement released on Sunday, the TSA added that travelers may be asked to power up some devices, such as cellphones, warning that powerless devices will not be allowed onboard the aircraft.

An unnamed official told the BBC that Heathrow, the U.K.’s largest airport, is among the airports affected by the security clampdown. With dozens of flights from Heathrow to the U.S. each day, thousands of travelers could potentially face disruption.

The other airports that could be involved were not immediately identified.

Adding to the confusion, relatively few details about the logistics of the U.K. clampdown have been released, such as whether powered-down devices will eventually be returned to their owners or destroyed. It’s also unclear whether charging stations will be available at airports to address the problem of powered-down phones.

“It's an idea that looks straightforward but is fraught with challenges,” warned Rob Bamforth, principal analyst at U.K.-based research and analysis company Quocirca, in an email to FoxNews.com. Devices with flat batteries, for example, would be a challenge to store and forward, he added.

When contacted to discuss how the TSA’s new security measures will be implemented, Heathrow airport advised FoxNews.com to contact the U.K.’s Department for Transport.

A spokesman for the Department for Transport told FoxNews.com that, at the moment, it is not discussing the specific logistics of the security checks. Its website offered a little more information, urging air travelers to the U.S. to ensure that their electronic devices are charged before they travel. “If your device doesn’t switch on, you won’t be allowed to bring it onto the aircraft,” it warned.

Quocirca’s Bamforth noted that extending air travel restrictions on the likes of scissors to much more expensive devices could result in some very unhappy travelers.

“This is acceptable for the odd set of nail scissors, pen knife and hair gel to be confiscated, but quite another matter with a £500 gadget,” he wrote. The potential for powered-down work devices to be confiscated could mean yet more woe traveler woe, he added.

Bamforth, however, noted that airports could start charging passengers money to power up their devices.

Follow James Rogers on Twitter @jamesjrogers