Passengers leaving for the U.S. from the Benazir Bhutto International Airport near Islamabad, Pakistan, now face increased security screening. (Anjum Naveed/Associated Press)U.S.-bound air travellers from 14 nations the U.S. considers to be sponsors of terrorism or "countries of interest" began facing tougher screening measures on Monday, prompted by the attempt to bomb a plane flying to Detroit last month.

The new rules mean that "every individual flying into the U.S. from anywhere in the world travelling from or through nations that are state sponsors of terrorism or other countries of interest will be required to go through enhanced screening," the U.S. Transportation Security Administration said in a statement on Sunday.

The U.S. State Department lists Cuba, Iran, Sudan and Syria as state sponsors of terrorism. The countries of interest include Afghanistan, Algeria, Iraq, Lebanon, Libya, Nigeria, Pakistan, Saudi Arabia, Somalia and Yemen.

Passengers from those countries will now be subject to enhanced screening techniques, including body scans, pat-downs and a thorough search of carry-on luggage.

The TSA also announced that passengers on U.S.-bound international flights will be subject to enhanced screen technologies and random screening.

Airports were also directed to increase "threat-based" screening of passengers who may be acting in a suspicious manner.

The U.S. government also added dozens of people to its terrorist watch and no-fly lists, a crackdown that comes as President Barack Obama prepares to meet Tuesday with his team of advisors about the state of national security.

The security measures follow the attempt to detonate an explosive on a U.S.-bound flight from Amsterdam on Christmas Day.

Umar Farouk Abdulmutallab, a 23-year-old Nigerian man, is accused of trying to ignite the bomb on the Northwest Airlines flight. Officials said he has told U.S. investigators he received training and instructions from al-Qaeda operatives in Yemen.

On Sunday, British Prime Minister Gordon Brown said full-body scanners will be introduced in Britain's airports.

Last week, the Dutch government announced it will begin using full-body scanners for flights heading to the United States.

With files from The Associated Press