Several European countries are refusing to follow the US and Britain in banning laptops and tablets from flights from several Muslim majority countries, sparking concern that the anti-terror measure will be rendered useless.
Germany, Spain, and Switzerland all announced on Wednesday that they will not be following the US and Britain in imposing the ban on large electronic devices being taken as hand luggage on board flights from six countries in the Middle East and North Africa.
France said it was still examining whether to impose the ban, but had reached no decision.
Outside Europe, allies of the US and UK in the 'five eyes' intelligence partnership have also responded, with Australia and New Zealand ruling out following suit and imposing the ban, while the measure is still under consideration by Canada.
The ban was reportedly imposed following intelligence that Isis was preparing to smuggle explosives on board a plane concealed in an electronic device.
Experts said that the decision of European countries not to follow suit could render the US and UK bans useless.
Michael Clarke, former director general of the Royal United Services Institute, the defence and security think-tank, told the Times that there was "potentially a huge loophole as it only applies to flights from those countries to the UK", adding: "What is stopping terrorists from flying here from there via a European country?"
The ban applies to any devices larger than a smartphone being taken on board flights from Turkey, Lebanon, Jordan, Egypt, Tunisia and Saudi Arabia. Airlines have until Saturday to impose the ban.
Twelve airlines are covered by the restrictions, including British Airways, Easyjet, Monarch, Jet2, Thomson and Thomas Cook. EasyJet on Wednesday became the first airline to impose the ban.
The US ban was imposed days before the UK ban, and covers different countries.