A Donald Trump rally in Virginia was repeatedly disrupted on Monday by protesters, including some from the Black Lives Matter movement, in a stark display of the divisions the Republican front-runner's presidential campaign has long been accused of sowing.

A Time magazine photographer trying to document the exit of dozens of black protesters from the rally in southwestern Radford, Virginia, was grabbed by the neck and shoved to the ground by a U.S. Secret Service agent.

Hecklers disrupted the rally on a day when the New York billionaire fended off criticism that he had not clearly condemned white supremacist support during an interview on CNN on Sunday.