Uncharged mobile phones, tablets and laptops will not be allowed on US-bound flights after a warning al-Qaeda could be planning to blow up an airliner.

The US Transportation Security Administration (TSA) said passengers at certain international airports may be asked during security screening to turn on their electronic devices.

If they do not have power the devices will not be allowed on planes, said the agency. The TSA would not specify which airports would be subject to the extra screening.

US security officials said last week they fear bombmakers from the Yemen-based al-Qaeda in the Arabian Peninsula (AQAP) have worked out how to turn phones into explosive devices which can avoid detection.

American authorities had already singled out Apple iPhones and Samsung Galaxy handsets for extra security checks.

In a statement on Sunday, the TSA said "As the travelling public knows, all electronic devices are screened by security officers. During the security examination, officers may also ask that owners power up some devices, including cell phones".

"Powerless devices will not be permitted onboard the aircraft. The traveller may also undergo additional screening".

Homeland Security Secretary Jeh Johnson recently ordered the TSA to implement extra security measures at some international airports with direct flights to the US.

"We know that there remains a terrorist threat to the United States. And aviation security is a large part of that" he told NBC.

The restrictions would apply to US-bound direct flights from Europe, the Middle East and Africa, the officials said. US authorities are also concerned that hard-to-detect bombs could be built into shoes or other items of clothing.

Last week, the Dublin Airport Authority (DAA) said they are working with the Department of Transport closely - but there will be no direct effect on passengers for the moment.