Air travellers across the world are facing tougher security measures and delays after a suspect Al-Qaeda terrorist came within moments of blowing up a transatlantic jet carrying 289 people on board.

President Barack Obama has interrupted his Christmas holiday to order two anti-terrorism reviews as aviation leaders attempt to close loopholes that failed to stop Umar Farouk Abdulmutallab, a Nigerian extremist, smuggle explosive materials on to Northwest Airlines Flight 253 from Amsterdam to Detroit on Christmas Day.

The attack came four days after a video was posted on extremist websites showing an al-Qaeda militant in Yemen saying: “We are carrying a bomb to hit the enemies of God.”

Abdulmutallab, formerly a student in Britain, was restrained by passengers and crew as he tried to detonate a bomb sewn into his underpants. He emerged from the toilet, put a blanket on his lap complaining of an upset stomach, then tried to operate the bomb. Passengers and cabin crew restrained him as flames leapt from his clothing.

Flights now are being delayed by up to four hours as passengers face extra screening and were limited to one item of hand luggage, including duty-free.

Under new measures, in the final hour before landing in the US, passengers are now banned from standing up, using toilets and holding blankets.

International travellers to the US are also undergoing newly required bag inspections, body searches and questioning at security checkpoints and before they board planes.

President Obama ordered a review of lists of terror suspects after it emerged that Abdulmutallab had been placed on a US intelligence database. But officials failed to move him to the “no-fly” list.

Some media reports suggest Abdulmutallab contacted Anwar Awlaki, the radical cleric in Yemen.

MI5 has launched an investigation to discover whether the failed bomber was part of a UK-based terrorist plot.

An al-Qaeda bomber from Yemen blew himself up near a Saudi minister this year after hiding PETN, the same explosive used in the Detroit attack, in his underpants.

Pilots on Sunday declared an emergency after a second man, also a Nigerian, spent an unusually long time in an airplane restroom, said a Department of Homeland Security spokeswoman, Sara Kuban.

The plane was taken to a remote corner of the airport where it was surrounded by emergency vehicles. All of the baggage was removed from the plane, lined up on the tarmac and searched by explosive-sniffing dogs.

The passenger, whose name was not made public, “was removed from the flight and interviewed” by the FBI.