House Minority Leader Nancy Pelosi (D-Calif.) and Democratic Congressional Campaign Committee Chairman Steve Israel (N.Y.) issued statements Sunday night calling for the House ethics committee to look into the conduct of Rep. David Wu (D-Ore.).

“I call on the Ethics Committee to initiate an investigation into the allegations against Congressman Wu,” Pelosi said in the statement. “With deep disappointment and sadness about this situation, I hope that the Ethics Committee will take up this matter.”

Wu is alleged to have had a sexual encounter with a woman against her will in late 2010, an episode first reported by the Portland Oregonian. The newspaper reported that Wu has acknowledged the encounter but insisted it was consensual.

One Democratic source said that Wu has decided not to seek reelection in 2012 and the Oregonian and Politico are reporting that he will not. But the congressman’s office did not return an e-mail seeking comment Sunday night regarding his plans. He is not expected to resign.

Wu has said nothing specific about the incident with the woman, issuing a statement Saturday calling it “very serious” and adding: “I have absolutely no desire to bring unwanted publicity, attention, or stress to a young woman and her family.”

This is the latest allegation of bizarre behavior by Wu at the end of last year — actions that include sending odd pictures to his staff and taking prescribed medication that had not been prescribed to him.

He has already drawn primary challenges from two Democrats — state Labor Commissioner Brad Avakian and state Rep. Brad Witt. Republicans hope to target the Democratic-leaning seat in the Portland area, but are likely to do so only if Wu is in the race.

Staff writer Aaron Blake contributed to this report.