A collection of press freedom groups has filed a congressional ethics complaint against Rep.-elect Greg Gianforte, R-Mont., for allegedly body-slamming a reporter asking him a question.

The groups PEN America, Free Press, Society of Professional Journalists and Reporters Without Borders filed a formal complaint with Congressional ethics officials on Friday. The complaint comes about a week after Gianforte allegedly body-slammed Guardian reporter Ben Jacobs, who was asking him a question about the recent Congressional Budget Office estimate of the GOP's health bill.

Gianforte was charged with assault, a case still pending in Montana.

"A member of the House hasn't physically assaulted someone this severely since the Civil War, and we are unaware of any historical precedent for a lawmaker beating up a reporter," said Gabe Rottman, PEN America's Washington Director, in a statement. "While Rep. Gianforte's apology was necessary, it was hardly sufficient."

Despite the incident, which happened the night before the special election for Montana's sole U.S. House seat, Gianforte beat Democratic challenger Rob Quist.

The groups filed the complaint with the Office of Congressional Ethics and wrote to the House Ethics Committee calling for an open investigation within 30 days of any member being charged with a crime, according to a statement.

The groups also sent a letter to President Trump to say his inflammatory statements directed at the media have been followed by violence against journalists, the Guardian reported.