Washington, March 1

An award-winning photographer covering a Donald Trump rally on Monday was thrown to the ground during an altercation with a Secret Service agent.

The incident took place as black protesters waving their fists and chanting marched through the arena at Virginia’s Radford University, while Trump supporters responded with boos.

According to a video posted on Twitter, the security officer told Time magazine photographer Christopher Morris to “get in the pen,” referring to the designated area for photographers.

Morris responded with a curse. The security agent grabbed him by the neck and slammed him to the ground in a choke hold.

The photographer kicked at the agent from the ground, then got up and momentarily grabbed the agent’s neck with one hand before the two were separated.

“I stepped 18 inches out of the pen and he grabbed me by the neck and started choking me and then he slammed me into the ground,” Morris told CNN.

Another video posted on YouTube showed Morris being led outside by uniformed police.

“The Secret Service is aware of an incident involving an employee of the Secret Service that occurred earlier today in Radford, VA,” the agency said in a statement.

“At this time, our local field office is working with their law enforcement partners to determine the exact circumstances that led up to this incident.”

Time said it has expressed concern to the Secret Service about “the level and nature of the agent’s response,” and that Morris “expressed remorse for his part in escalating the confrontation.”

“We are relieved that Chris is feeling OK, and we expect him to be back at work soon,” an unnamed Time spokesperson said.

Trump’s campaign requires reporters and photographers to stay inside a gated area, a sharp contrast to his rivals who usually allow the press to move about freely at events.

Trump, like other major presidential candidates, is protected by the Secret Service.

They serve as bodyguards but also supervise local police who provide security at the candidates’ events.

Morris, a veteran Time photographer, has won various awards for his work and is a founding member of the VII photojournalist agency.