The US-UK ban on electronic devices larger than a mobile phone for some flights from Africa and the Middle East stems, in part, from the discovery of a terror plot to use an iPad to blow up an airliner.

The Guardian, citing an anonymous "security source," said Monday that the uncovered plot involved explosives hidden in a fake iPad "that appeared to be as good as the real thing." The Guardian's source did not provide other details, like when and where the threat was discovered and who was behind it.

Discovery of the plot confirmed the fears of the intelligence agencies that Islamist groups had found a novel way to smuggle explosives into the cabin area in carry-on luggage after failed attempts with shoe bombs and explosives hidden in underwear. An explosion in a cabin (where a terrorist can position the explosive against a door or window) can have much more impact than one in the hold (where the terrorist has no control over the position of the explosive, which could be in the middle of luggage, away from the skin of the aircraft), given passengers and crew could be sucked out of any subsequent hole.

Security concerns over weaponized electronics on airlines have some merit. For starters, electronics are ubiquitous. And last year, for example, a bomb in a laptop punctured a hole in the passenger area on a Somalia-bound flight.

The US and UK governments last week announced the ban on most electronic devices from being allowed in airline cabins. The US Department of Homeland Security adopted the so-called "aviation security enhancements" that require any device larger than a cell phone to be put in checked baggage for US-bound flights from 10 selected airports worldwide. The barred devices include laptops, tablets, e-readers, cameras, portable DVD players, and any electronic game bigger than a mobile phone.

Selected countries, airports

The affected airports are Queen Alia International Airport in Amman, Jordan; Cairo International Airport; Ataturk International Airport in Istanbul; King Abdul-Aziz International Airport in Jeddah, Saudi Arabia; King Khalid International Airport in Riyadh, Saudi Arabia; Kuwait International Airport; Mohammed V Airport in Casablanca, Morocco; Hamad International Airport in Doha, Qatar; Dubai International Airport; and Abu Dhabi International Airport.

In the UK, the onboard electronics rule applies to inbound flights from Egypt, Jordan, Lebanon, Saudi Arabia, Tunisia, and Turkey.