Passengers using airports that offer direct flights to the US may be forced to switch on their mobile phones and other electronic devices to prove to security officials that they do not contain explosives, it was announced yesterday.

“During the security examination, officers may also ask that owners power up some devices, including cell phones,” the US Transportation Security Administration (TSA) said in a post on its website.

It warned: “Powerless devices will not be permitted onboard the aircraft. The traveller may also undergo additional screening.”

The TSA did not disclose which airports would be conducting the additional screening.

It was reported last week that passengers at British airports travelling to the US were facing extra checks on phones. Belgian officials said passengers there would also have devices checked.

The new measure is the first to be confirmed since Jeh Johnson, the US Homeland Security secretary, warned last week that enhanced security checks would be implemented imminently at “certain overseas airports with direct flights into the United States”.

“We are sharing recent and relevant information with our foreign allies and are consulting the aviation industry,” Johnson said on July 2nd. “We will work to ensure these necessary steps pose as few disruptions to travellers as possible.”

US officials told reporters that Johnson’s move followed intelligence that al-Qaeda operatives in Syria and Yemen may have developed bombs that could be placed in mobile telephones and avoid detection to bring down aircraft bound for America.

Reuters reported last week that US officials had singled out Apple iPhones and Samsung Galaxy devices as needing particular attention during security checks on passengers for direct US-bound flights from Africa, Europe and the Middle East.

The officials were reported to be concerned that bomb-makers from both the Yemen-based al-Qaeda in the Arabian Peninsula and the Islamist Nusra Front, an al-Qaeda affiliate in Syria, had been collaborating to develop the explosives and plots to detonate them.

The US government said yesterday that yet more security checks may be introduced in future. “TSA will continue to adjust security measures to ensure that travellers are guaranteed the highest levels of aviation security conducted as conveniently as possible,” the administration’s announcement said.

Guardian