American Airlines has been forced to publicly apologise after an onboard incident between a passenger and flight attendant was filmed, posted on social media and subsequently went viral.

In the video posted to Facebook – which has been viewed nearly four million times – footage shows a mother-of-two at the front of the plane sobbing as she holds her baby. Initially, it’s unclear why the woman is upset.

However, Surain Adyanthaya, who posted the video to Facebook, said that before the footage, the flight attendant had “violently” taken the stroller, hitting the woman in the process and “just missing her baby”.

In an another post, Adyanthaya wrote they “escorted the mother and her kids off the flight”, letting the flight attendant back on despite the fact he had “tried to fight [another] passenger”.

Another passenger, Olivia Morgan, told KTLA-TV the flight attendant in question was “violent” when taking the stroller.

“The flight attendant wrestled the stroller away from the woman, who was sobbing, holding one baby with the second baby in a car seat on the ground next to her,” she told the news outlet.

“He stormed by me with the stroller and I said something like, ‘What are you doing? You almost hit that baby!’ And he yelled at me to ‘stay out of it!’ just like he does in the video.”

On its website, American Airlines says a customer is able to carry a “small, collapsible and light stroller” onto the plane. However, any stroller that is “non−collapsible must be checked at the ticket counter”.

Another passenger onboard,  Tom Watson, says the situation began to escalate when the woman refused to let go of the stroller when asked to put it away.

“The woman was holding on to the stroller and refusing to let go,” he told KTLA-TV.

In responding to the video and the inevitable backlash that came once it went viral, American Airlines said they have seen the video and begun their own internal investigations.

“We have seen the video and have already started an investigation to obtain the facts. What we see on this video does not reflect our values or how we care for our customers. We are deeply sorry for the pain we have caused this passenger and her family and to any other customers affected by the incident,” the airline said in a statement.

They added they are making sure all of the woman’s “needs are being met while she is in [their] care”, saying they intend to upgrade her family to first class for the remainder of her trip. It’s believed the woman is from Argentina and is flying internationally.

"The actions of our team member captured here do not appear to reflect patience or empathy, two values necessary for customer care. In short, we are disappointed by these actions. The American team member has been removed from duty while we immediately investigate this incident," the airline finished.

The incident comes a matter of weeks after another US airline, United Airlines, were forced to apologise after overbooking a flight and physically forcing passengers to get off.

Footage from the United Airlines flight earlier this month shows a bloodied passenger, Dr David Dao, being violently removed and dragged from the flight.

In an interview with ABC’s Good Morning America after the incident, United CEO Oscar Munoz said he was “ashamed” and apologised to Dr Dao and his family profusely.

“That is not who our family at United is,” he said.