Updated March 30: Revised to include TSA statement about the agency speaking with Jennifer Williamson.

A mother who asked TSA agents at DFW International Airport for alternative screening for her son with special needs said they were "treated like dogs" and forced to miss a flight during an extensive security check, according to her Facebook post that has since gone viral.

But the Transportation Security Administration said in a prepared statement that it followed approved procedures to "resolve an alarm of the passenger's laptop."

The agency said in a statement Thursday that it had spoken to Williamson about the incident to "learn more about her family's screening experience," KXAS-TV (NBC5) reports.

Jennifer Williamson wrote Sunday morning that her son has a sensory processing disorder and that she asked agents to "screen him in other ways per TSA rules."

An accompanying video shows a TSA agent patting down her son. The agent pats down his backside before moving to his front. She writes in the post they were kept for more than hour in the "horrifying" incident.

TSA disputed Williamson's account, noting in its statement Monday that the passengers were at the checkpoint for about 45 minutes, including the time it took to discuss screening procedures with the teen's mother and the inspection of three carry-on items. The pat-down took about two minutes, according to the agency.

Williamson's post has more than 100,000 shares.

"Let me make something else crystal clear," she wrote. "He set off NO alarms. He physically did not alarm at all during screening, he passed through the detector just fine. He is still several hours later saying 'I don't know what I did. What did I do?' I am livid.

"I wish I had taped the entire interchange because it was horrifying. We had two DFW police officers that were called and flanking him on each side. Somehow these power tripping TSA agents who are traumatizing children and doing whatever they feel like without any cause, need to be reined in."

TSA said two police officers were called to mitigate the mother's concerns.

"The video shows a male TSA officer explaining the procedure to the passenger, who fully cooperates," the agency's statement reads. "Afterward, the TSA officer was instructed by his supervisor, who was observing, to complete the final step of the screening process."

Williamson could not be reached for comment.

In its statement Friday, the TSA reiterated that the correct procedures were followed, adding that "we appreciate her feedback and look forward to continued dialogue."

The statement continued: "TSA has a long standing partnership with a coalition of disability advocacy groups, community-based organizations and individuals, and we welcome Ms. Williamson's input. TSA is committed to ensuring the security of travelers, while treating all with dignity and respect."

Staff writer Tom Steele contributed to this report.

CORRECTION, 7:50 p.m. March 27: Because of an error in a TSA statement, an earlier version of this story incorrectly said that the family was at the airport checkpoint for 35 minutes. The agency said the passengers were at the checkpoint for 45 minutes.