(Reuters) - University of North Carolina police charged three people in connection with the toppling of a Confederate soldier statue on the Chapel Hill campus, an official said on Friday, as the school braces for another on-campus rally over the weekend.

At a rally earlier this week, protesters used a rope to pull down the statue known as Silent Sam, erected in 1913 to honor soldiers of the pro-slavery Confederacy killed during the Civil War.

Each of the three people faces misdemeanor charges of riot and defacing of a public monument, university police spokesman Randy Young said in an emailed statement.

The three are not affiliated with the University of North Carolina, Young said. A police investigation may result in additional arrests.

The incident was part of a movement to dismantle U.S. Civil War symbols that critics say glorify the South’s legacy of slavery. Many Americans see statues such as Silent Sam as symbols of racism and a glorification of the South’s defense of the institution of slavery. Supporters view the memorials as important symbols of American history.

The university said in a statement on Friday that it expected a rally on Saturday on campus and in town and it was working with local officials and law enforcement to ensure safety.

“We do not know for sure what groups may attend, but we are mindful that the current atmosphere is highly charged,” the university said, urging people to stay away.

Some students and others have received threats because of Monday’s events, the university said.

University police reviewed video on Tuesday to identify the protesters who toppled the statue.

The UNC system board chair, Harry Smith Jr., and president, Margaret Spellings, denounced the toppling of the statue.

The university will reinstall Silent Sam within 90 days as required by North Carolina law, UNC system board member Thom Goolsby said in a statement on Thursday.

Last year UNC students threatened to sue the school, alleging that the university violated federal anti-discrimination laws by allowing the statue to remain on campus.

Campus police arrested at least one person at Monday’s protest for wearing a mask and resisting arrest. The person arrested was not one of the three people charged, Young said.