Immigration and Customs Enforcement agents have been deployed to major US airports nationwide to assist the Transportation Security Administration during a partial government shutdown.President Donald Trump directed the deployment to alleviate massive wait times, which have reached three hours in some cities.Federal agents from Homeland Security Investigations are now visible at hubs including John F Kennedy International and Chicago O'Hare.While these officers manage crowds to free up specialized personnel, the move has drawn sharp criticism from the American Federation of Government Employees.The Department of Homeland Security defended the measure as necessary for aviation safety, despite union concerns about lack of training.