A Time magazine photographer trying to document the exit of dozens of black protesters from the rally in Radford, Virginia, was grabbed by the neck and shoved to the ground by a US Secret Service agent.
The hecklers, including some from the Black Lives Matter movement, interrupted the rally amid criticism that the New York billionaire has not clearly condemned a white supremacist that reportedly endorsed him.
Black Lives Matter is a civil rights movement that formed in 2013 to protest police violence against African Americans.
Trump mocked the black protesters as they were escorted from the rally, shouting "Are you from Mexico?" at one of them.
The protesters disrupted Trump's remarks several times for long stretches, prompting him to shout to security guards several times, "Get them out please, get them out."
Time magazine photographer Chris Morris was on the edge of an enclosed media section when he was grabbed by an agent from the Secret Service, which has the job of protecting US presidents and some presidential candidates.
“I stepped 18 inches out of the (press) pen and then he grabbed me by the neck and started choking me and then he slammed me to the ground," Morris told CNN at the scene.
The Trump rally took place on the eve of Super Tuesday, the biggest state primary voting day in the race to pick the 2016 presidential nominees for the November national election. Opinion polls show Trump is likely to win the Republican nomination in July.