INDIANAPOLIS — Indiana Republican Rep. Mark Souder said he will resign from Congress effective Friday over an affair with a staffer.

Souder said in a statement provided by his office this morning he "sinned against God, my wife and my family by having a mutual relationship with a part-time member of my staff."

He scheduled a news conference to discuss his future.

Souder won a bruising Republican primary on May 4 to be nominated for his ninth term representing northeastern Indiana.