A passenger aboard a United Airlines flight claims she was forced to urinate in a cup because attendants told her she couldn't leave her seat with the "fasten seatbelt" sign turned on. The airline says it is now investigating the April incident.

Kansas City resident Nicole Harper, a mother of two children, told CBS affiliate KCTV that she was humiliated in front of other passengers during the United Airlines flight from Houston to Kansas City. Harper claims she suffers from an overactive bladder and had already gotten up to use the restroom when the plane hit turbulence and a flight attendant told her she had to return to her seat.

When Harper, who was traveling with her family, explained that the situation was an emergency and that she needed to urinate, the flight attendant allegedly handed Harper a plastic cup. Her husband reportedly helped her fill two cups with urine before an airline official demanded she empty the cups in the lavatory, threatened her and shamed her in front of the flight’s other passengers.

“It's a little embarrassing to come forward,” she told KCTV.

Harper said the incident occurred during drink service approximately 30 minutes into the flight. In a statement to International Business Times, the airline said it happened during descent.

Other passengers had gotten up from their seats, Harper claims, and she was ready for her turn to use the restroom when the attendant “told me very rudely it was not allowed to get out of my seat.”

“Well, I'm going to need a cup then,” Harper reportedly told the attendant.

Harper told KCTV that she was wearing a dress that allowed her to squat over the seat and use a cup. Her husband helped her fill two. Harper says the incident was humiliating.

Read: United CEO Responds To David Dao Incident As New Video Surfaces

“I was thinking I was on candid camera or being punked at this point,” she told KCTV. She said that after the attendant made her stand up and empty the cups, the individual told Harper they would report her, that she’d have to speak to the pilot upon landing and that the seat would have to be cleaned by a biohazard team.

“Customer safety is always our first priority,” United Airlines told IBT in a statement. “Initial reports from the Mesa Airlines flight attendants indicate that Ms. Harper attempted to visit the lavatory on descent and was instructed to remain seated with the seat belt fastened per FAA regulations. At no point during the flight did flight attendants suggest that Ms. Harper use cups instead of the lavatory. We have reached out to Ms. Harper to better understand what occurred and we continue to review what happened.”

This most recent incident occurred on the heels of the controversial incident involving Dr. David Dao, who was injured and bloodied after being pulled off an overbooked United flight. Cellphone video of Dao dragged off the overbooked flight went viral and the carrier later made a public apology. 

Dao and United Airlines reached an “amicable settlement” April 27 for an undisclosed amount.