A man who was put in a headlock and shoved off a Muni train in San Francisco by two men declined to press charges, police said Friday, but authorities are continuing to investigate the incident to see what led to the altercation.

Social media videos of the incident caused an uproar online, as it was suggested the man thrown from the train was a “kid” who had been playing music. He could be heard pleading on video “stop, stop, stop” when the two men attempted to throw him off the train. Two other videos showed him being put in an aggressive headlock by one of the two men.

Officers received several calls regarding an assault about 8:45 p.m. on the N Judah Muni line near Judah Street and 34th Avenue, said Officer Robert Rueca, a San Francisco police spokesman.

The man who was beaten on the train provided authorities with a statement, but declined to file charges against the men, Rueca said.

Officers also interviewed the man who is seen on video inflicting the headlock. The third man involved in the altercation was not found.

“I think the videos look disturbing, but at the same time there’s usually more to a story because people don’t just start fighting each other, so we are trying to investigate more,” Rueca said.

He added that there is no information yet on what prompted the altercation.

Muni is providing authorities with surveillance footage and more details will be released as they become available, said Paul Rose, a Muni spokesman.

“This is a very disturbing video,” he said. “We are working with (San Francisco police) to fully investigate this matter.”

Rueca said police are waiting to review the surveillance footage. Neither of the men interviewed, including the one thrown off the train, complained of any injuries or were transported to the hospital, he added.

Two videos were first posted Thursday night on Twitter by independent journalist Anna Sterling. She said the footage was sent to her by a witness at the scene.

While it’s not clear what caused the confrontation, people in the background of the videos can be heard saying the “kid” was playing music.

“Whoa these two men just tried to throw this kid off the muni [sic] train because he was playing music too loudly,” Sterling tweeted.

The videos have since been shared thousands of times.

Whoa these two men just tried to throw this kid off the muni train because he was playing music too loudly. He easily could’ve hit oncoming traffic. This is not okay. pic.twitter.com/NYIZilSmNL — Anna Sterling (@AnnaMSterling) August 31, 2018

The first video shows one man putting the young person in a choke hold against the bench of the train. Witnesses can be heard pleading “leave him alone” and “he’s just a kid.”

The man holding him in a chokehold against a seat says, “Tell him to stop. I’ve got no problem.”

A second video posted by Sterling shows the same man and another man wearing a gray sweater forcing open the doors of the train and struggling to push the young person out of the car.

They’re attempting to throw him onto the street. You can see it clearly here. He’s just a kid. This is not okay. pic.twitter.com/BGT3kado26 — Anna Sterling (@AnnaMSterling) August 31, 2018

The witness who recorded the videos, Sterling said, got off the train and attempted to help to the young person.

Sarah Ravani is a San Francisco Chronicle staff writer. Email: sravani@sfchronicle.com Twitter: @SarRavani