Under the new rules, all citizens of Afghanistan, Algeria, Lebanon, Libya, Iraq, Nigeria, Pakistan, Saudi Arabia, Somalia and Yemen must receive a pat down and an extra check of their carry-on bags before boarding a plane bound for the United States, officials said. Citizens of Cuba, Iran, Sudan and Syria — nations considered “state sponsors of terrorism” — face the same requirement. In a statement, the Transportation Security Administration (TSA), part of the giant Department of Homeland Security (DHS), said a majority of all other U.S.-bound international travelers — not just from the 14 countries — will also face random and threat-based enhanced screening.