(CNN) -

Air passengers heading for the United States are to be subjected to new security checks that could see them delayed if their electronic device has a dead battery.

A U.S. government official has told CNN the measures are in response to new intelligence that terror groups are trying to build new, harder-to-detect explosive devices.

With stringent airport security already viewed as an inconvenience -- albeit a necessary one -- by many passengers, the new checks have been greeted with concerns over delays, disrupted schedules and the potential loss of expensive and irreplaceable devices.

So how will the new measures affect travelers?

Here are a few answers:

Which passengers will be affected?

In theory the checks apply to all air passengers flying directly to the United States from outside of the country.

Those on domestic flights within the United States will not be subjected to the same scrutiny.

The U.S. Department of Homeland Security, which is requiring airlines or security officials to perform the checks before boarding, says the measures are already in place at some international airports and will be formulated at others in coming days.

The focus of the new measures is on airports in Europe, Africa and the Middle East.

Key aviation hubs in the UK, Netherlands, Germany and France have already confirmed they're implementing the measures.

Security agencies have declined to detail whether every passenger will be subject to heightened screening, but one analyst said this is unlikely.

"I think it's going to be a more of random selection," aviation security consultant Jeff Price told CNN. " I don't think everyone's going to be required to walk up there with their cellphone in their hand."

Which devices will be checked?

All electronic equipment could be subject to examination, including laptops, cellphones, tablets and MP3 players.

Passengers are being advised to make sure these are all charged before travel so that they can be switched on and demonstrated to be operational.

The DHS says there's an increased focus on enhanced explosive trace detections, meaning the devices could also be swabbed for chemicals.

Some reports have indicated that Apple and Samsung products are being specifically targeted, but the U.S. Transport Security Administration has declined to respond to questions about this.

Price said it's possible that intelligence reports have picked up on specific brands.

"Typically what will occur is that someone will come up with a new type of device and they'll publicize that within their community and try to get others to do it as well," he said.

"They'll most likely have designed it to go in certain devices, which is probably what the intelligence has indicated, that's why they'd look at specific brands."

What happens if the battery is dead?

The DHS says it doesn't dictate to individual countries how they handle electronics that do not power up, other than to say the devices can't go on the plane. It's up to individual countries to decide what to do with the devices.

Anyone with an uncharged device risks being subjected to extra scrutiny and possibly held back from boarding their flight, according to the DHS and airline officials.

Those who get to the airport with a dead battery have several options.