A three-year-old wheelchair-bound boy was subjected to a thorough pat down by the Transportation Security Administration (TSA) at the Chicago's O'Hare Airport before he was allowed to get on a plane with his family.

A video filmed by the boy's father shows the toddler looking distressed during the security check. His father's voice can be heard trying to comfort him through the pat down.

"I was told I could not touch him or come near him during the process," the boy's father told RT News. The father also said his son was "trembling with fear" and wanted him "to hold his hand and give him a hug".

The family of six was travelling through Chicago's O'Hare Airport when a TSA officer said he needed to pat down the boy.

The officer first patted down the child. He then conducted a search for traces of explosives by swabbing the boy's palms, feet and back. The officer requested the father to lift the boy's shirt so he can swab his back and said he would have to take the boy into a private screening area if the father refused to lift the child's shirt.

"Apparently, there are a lot of children in wheelchairs being used to bring down planes," the boy's father remarked after the incident.