Hundreds of Transportation Security Administration agents who are not getting paid during the government shutdown are calling out sick at major airports across the U.S. CNN first reported the increase in call outs which have raised concerns about airline security.

Union officials representing TSA employees told the media outlet a large number of workers have called out sick this week at New York's John F.

Kennedy Airport, Dallas-Fort Worth International, as well as the Charlotte and Raleigh-Durham airports in North Carolina.

A TSA spokesperson acknowledges absences have gone up, but insists security will not be affected, and the agency will continue to monitor the situation.

Union officials say although the mass callouts are not part of an organized protest, they believe more agents will call out sick the longer they don't receive paychecks.

TSA agents are among the hundreds of thousands of federal workers who are working without pay as the government shutdown heads into its third week.