Violinist says United Airlines employee 'lunged' at instrument in carry-on dispute "United attacked yet another passenger," her attorney claimed.

 -- A classical violinist claims a United Airlines supervisor attempted to wrestle her violin from her arms, possibly injuring her hand, after saying she couldn't carry on the instrument -- and she's looking for footage to prove it.

Yennifer Correia, a Venezuelan musician who was en route to a gig with the Missouri Symphony Orchestra, was boarding her flight from Houston to St. Louis on Sunday when a United gate agent attempted to prevent her from boarding with her violin.

Correia asked what her other options were after airline employees told her should could not carry on the valuable instrument, since she did not feel comfortable checking it, according to her attorney, Phillip MacNaughton. He said the instrument is believed to date back to the 1700s and is worth tens of thousands of dollars.

The airline employees said there were "no options," he said. As the situation escalated, a United supervisor called to the scene allegedly "became belligerent" and "lunged" for the case, as Correia screamed for help.

In an apparent nod to another United Airlines incident involving a paying customer, Dr. David Dao, who was bumped from a flight to make room for crew members, MacNaughton said in a statement, "United Airlines attacked yet another passenger."

He added that Correia has an appointment with a hand specialist to examine whether any damage was caused considering the stakes for her career.

Federal law requires U.S. carriers like United to allow "a small musical instrument, such as a violin or guitar" as carry-on in the cabin, even if it exceeds the airline's standard size limits, as long as its weight does not exceed the stowage space's maximum weight capacity.

"We’re disappointed anytime a customer has an experience that does not live up to his or her expectation," United said in a statement, noting that the airline fully refunded Correia's ticket and reached out "to gain a better understanding of what occurred and to offer assistance."

McNaughton is urging anyone with video of the what he called an "attack" to come forward.

"A United supervisor chose to escalate a simple issue about how to safely transport a violin ... into a physical attack," he told ABC. "Ms. Correia understands that it has become her obligation to be the person who stands up for musicians traveling with their instruments and for all of us who expect at least simple courtesy when traveling by air."

ABC News' Rachel Katz contributed to this report.