Investigation launched after video appears to show officer leaning on man's neck

Authorities are investigating after a video appears to have captured a police officer kneeling on a man's neck while attempting to restrain him.

The incident happened Saturday evening in Allentown, Pennsylvania, outside Saint Luke's Hospital - Sacred Heart Campus.

In a 26-second viral video posted on Twitter by the group Black Lives Matter to Lehigh Valley, three police officers are seen attempting to restrain a man on the ground. One of the officers appears to put his elbow, and then his knee, on the man's neck.

After the video was shared, protesters demonstrated Saturday night in front of the police precinct in downtown Allentown.

"The video that has now been shared at the national level was scary, alarming and reduced trust not only for the residents of Allentown, but for people across this country who shared our same sentiments," Black Lives Matter to Lehigh Valley said in a statement on Facebook Sunday.

The group called for the release of the body cam footage and more information on the incident, among other things. The organization cited the police department's use of force policy, which prohibits the use of neck restraints unless to prevent "imminent death or serious bodily injury to a member or citizen."

Ben Crump, the attorney for George Floyd's family, also shared the video on Twitter Sunday, saying this was "exactly what led" to Floyd's death. Floyd died in May after he was pinned down by a Minnesota police officer who prosecutors say held his knee on Floyd's neck for nearly nine minutes.

Sunday evening, the Allentown Police Department released a statement regarding the incident. It did not name the officers involved, but said that the man was restrained after he began to "yell, scream and spit at the officers and hospital staff."

"The individual continued to be non-compliant, which required officers to restrain the individual and the hospital applied a spit shield," police said.

The man was ultimately treated in the hospital and later released, police said.

The department is conducting an internal investigation on the use of force, which will be reviewed by the Lehigh County District Attorney, officials said. Police said they are interviewing witnesses and reviewing additional videos of the incident. They plan to release "relevant videos" later this week.

"Part of the investigation has included the review of a 23-second video posted to social media. Although significant, the entirety of the interaction is being reviewed," the statement said.

The statement does not specify if any of the officers were suspended during the investigation. ABC News was unable to reach the Allentown Police Department for comment.

The district attorney is expected to complete his review later this week.

Black Lives Matter to Lehigh Valley is planning another protest over the incident on Monday.

ABC News' Greg Bradbury contributed to this report.