US-bound passengers will soon be banned from travelling with most electronic devices on flights from several Middle Eastern and North African countries, according to reports.

It is understood the increased security measure is in response to an unspecified terrorism threat and will affect nine airlines operating out of 10 airports.

Passengers will still be able to carry mobile phones, but larger devices such as laptops, cameras and electronic games will only be permitted in checked baggage only.

In a tweet published on Monday, Royal Jordanian warned its passengers the ban will be "effective starting [on] March 21."

However the tweet appears to have been deleted, with the airliner now telling its customers "further updates will be announced soon".

The Department of Homeland Security is expected to make an announcement later on Tuesday.