A substitute teacher in the US who was fired for allegedly putting duct tape over a student's mouth has accused the school's principal of doing the same to him.

CBS News has reported that the teacher put tape over a second-grader's mouth before the having tape placed over his mouth by the principal.

"You don't duct tape nobody's kids," said a school board member. "They're sitting back there acting like nothing happened, it doesn't take from Dec. 2 to the 18th to notify a parent their child had duct tape on their mouth."

The teacher in turn filed a police report accusing the principal of assault, claiming his lip was cut. But police said there wasn't sufficient evidence to lay assault charges against the principal.