Five North Carolina Sheriff's deputies have been disciplined over their behavior at a rally for Republican presidential candidate Donald Trump where a white supporter sucker punched a black protester, officials said on Wednesday.

The Cumberland County Sheriff's Office said three deputies were demoted and suspended for five days each without pay for their unsatisfactory performance at last week's rally while the two others were suspended for three days.

"The actions of the deputies and their failures to act in situations such as that which occurred during the Trump rally at the Crown Coliseum have never been and will not ever be tolerated under the policies of this office," Sheriff Earl "Moose" Butler said.

RELATED: Trump predicts riots if denied presidential nomination: CNN interview

At the rally in Fayetteville, John McGraw, a 78-year-old white Trump supporter, was arrested on a misdemeanor assault charge after he was seen on video punching a 26-year-old black protester in the face.

Video of the incident recorded by bystanders showed deputies pinning the assaulted protester to the ground, prompting social media criticism on why swift action was taken against him instead of his assailant.

All five of the deputies were admonished for their behavior and have been placed on probationary status for the next 12 months, the Sheriff's Office statement said.

Sheriff's officials on Monday decided against criminally charging Trump or his campaign with "inciting a riot" at the rally.

Trump has rejected suggestions that his language was to blame for recent clashes at his rallies. The 69-year-old New Yorker leads a field of four Republican candidates vying for the party's presidential nomination.