Four prison guards were attacked by three inmates over the weekend in Atlanta’s federal penitentiary, according to the union.

Local 1145 Union President Vance Bryant said three separate incidents were reported Friday and Saturday.

Two correctional officers were punched in the face and a third was pushed forcibly before getting the inmate under control, Bryant said in a news release.

Bryant told Channel 2 Action News the prison is having weekly incidents related to inmates’ use of synthetic marijuana.

“Since it’s not an illegal substance, it’s very difficult for us to detect it,” Bryant told the news station. “And it’s very difficult for us when the inmates are caught using or possessing it.”

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