US authorities have announced enhanced security measures, but the TSA's power at airports outside the US may be limited

US transportation authorities said last week that they had enhanced security measures at certain overseas airports. Details on some of those measures were unveiled on Sunday, raising questions about the amount of authority the US Transportation Security Administration (TSA) has outside the US.

What are the new security rules?

People traveling on nonstop flights from foreign airports to the US may have to turn on their mobile phones and other electronic devices for security officials. “Powerless devices will not be permitted onboard the aircraft,” the TSA said. “The traveller may also undergo additional screening.”

Why are they being implemented?

US officials have told reporters that they are concerned about new attempts by al-Qaida operatives to create a bomb that can go through airport security undetected. Britain's deputy prime minister Nick Clegg said last week that tightened security at UK airports may not be temporary. “I don't want people to think that this is just a sort of a blip for a week,” Clegg said. “This is part of an evolving and constant review about whether the checks keep up with the nature of the threats we face."

How much authority does the TSA have outside the US?

The agency can make sure “certain procedures” are set in line with TSA policies and procedures, especially for nonstop flights to the US, said a Department of Homeland Security official. The official said the TSA relies on local airports, airport authorities and carriers to implement the screening procedures handed down by the agency.

Are TSA workers stationed at foreign airports?

No, the agency does not have personnel overseas, nor does it have screening operations overseas, the official said.

What happens to my device if the charge has run down?

The TSA official told the Guardian that what happens to the device is determined by the people involved in the screening process overseas – airlines, airports and passengers – since no TSA employees is stationed in foreign airports. “Our policy is no powerless devices on board – full stop.”