The Associated Press reports Americans should be alert to the possible travel risks, especially during the holidays, following increased threats from militant groups around the world, the State Department warned on Monday. A travel alert, which is to be in effect until Feb. 24, said current information suggests that militants with the Islamic State, al-Qaida, Boko Haram and other groups continue to plan attacks in multiple regions. U.S. authorities said the likelihood of such attacks will continue as members of IS return from Syria and Iraq, and other individuals not affiliated with terror groups engage in violence on their own. "U.S. citizens should exercise vigilance when in public places or using transportation," the alert said. "Be aware of immediate surroundings and avoid large crowds or crowded places. Exercise particular caution during the holiday season and at holiday festivals or events."