A Democratic congressman in a tight re-election race admitted Tuesday that when he was a college student 28 years ago, he was disciplined by school officials for "inexcusable behavior" toward an ex-girlfriend.

The admission by Rep. David Wu (search), D-Ore., came after The Oregonian newspaper ran a story saying a former girlfriend from college once claimed Wu tried to force her into having sex. The story said the woman, whom the newspaper did not identify, declined to comment.

In a statement, Wu said he had a "two-year romantic relationship that ended with inexcusable behavior on my part."

"I take full responsibility for my actions and I am very sorry," Wu said. "I was disciplined by Stanford University for my behavior, and I worked with a counselor. This single event forever changed my life and the person I have become."

He did not elaborate on what he had done or what school officials did to discipline him. The paper said he lost a pending appointment as a dormitory resident assistant.

Wu, 49, is facing a tough challenge this year from Republican Goli Ameri (search). He is seeking his fourth term.

The newspaper said none of the information in its story came from Ameri or any Republican officials or activists.

Ameri's campaign spokesman, Jonathan Collegio, said the GOP challenger had no comment on the report. "We are focused on winning the election, and on how to revive the northwest Oregon economy," Collegio said.

A former patrol commander at Stanford, Raoul Niemeyer, told The Oregonian that the 21-year-old Wu was brought to the campus police annex in the summer of 1976 after his ex-girlfriend alleged that he tried to force her into sex. They had broken up that spring, it said.

According to Niemeyer, Wu told police that what happened was consensual.

Niemeyer did not see or meet with the woman but said his officers told him that she was bruised and that she and Wu previously "had some type of a relationship."

"Whether it was an amorous one or whether it was just platonic or what, I never was able to determine because, you know, the guy, he basically clammed up after that and wouldn't talk," Niemeyer told the paper.

Wu was not arrested. The woman ultimately declined to press charges and did not file a formal complaint with the school, former Stanford officials said.

But before the next school year began, Wu was "de-selected" for a job as a dormitory resident assistant, Lyman Van Slyke, a history professor who oversaw the dormitory, told the newspaper.

Current Stanford officials would not discuss what happened between Wu and the woman or the university's handling of the matter, citing university policy and student confidentiality laws, the newspaper said.