U.S. Rep. David Wu, D-Ore., is at the forefront of another sex scandal -- and it appears that it isn't the first time he has found himself in such a quagmire.

According to the Portland Oregonian, a young woman called Wu's Portland office this spring, accusing him of what was described as an "unwanted sexual encounter."  The woman, unnamed by the paper, reportedly left a distraught voicemail accusing Wu of aggressive sexual behavior.

When confronted by his senior staff, Wu admitted to a sexual encounter, but maintained that it was consensual, The Oregonian cited anonymous sources saying. The woman, a daughter of a longtime friend and campaign donor, did not call the police immediately, as she saw it being her word against those of a seven-term congressman.

In a statement late Friday, Wu did not directly address his action in the matter.

"This is very serious, and I have absolutely no desire to bring unwanted publicity, attention, or stress to a young woman and her family," Wu said.

Wu, 56, separated from his wife in 2009 and has been seeking a divorce.

The news comes after a tumultuous year for Wu, whose political career was threatened in 2010, when staffers accused him of erratic behavior toward the end of his successful re-election campaign. Staffers urged him to check into a psychiatric hospital because of his behavior, but Wu cited stresses of the campaign for his behavior and said he sought treatment for his problems.

In 2004, The Oregonian reported on a 1976 case when Wu was a student at Stanford University and was disciplined for trying to force an ex-girlfriend to have sex.

A source close to Wu told The Associated Press that the Democrat was planning to meet congressional leaders in Washington D.C., on Saturday to discuss the allegation, following House Minority Leader Nancy Pelosi's request for an ethics investigation and reports that Wu will not be seeking re-election next year.

"With deep disappointment and sadness about this situation, I hope that the Ethics Committee will take up this matter. I will send a letter to the Ethics Committee tomorrow asking them to formally initiate a review of this matter," Pelosi said in a written statement Sunday.

The allegations place Wu as the new face of Congress sex scandals, as it comes a month after former Rep. Anthony Weiner, D-N.Y., resigned after posting lewd photos of himself to his Twitter account.

And like Weiner, Wu has been facing calls for his resignation.

Two prominent Democrats running against Wu said the congressman should step aside if the sex allegations are true, Fox News reported.

"I'm saddened to hear this news. David owes the citizens he represents a detailed explanation," said State Rep. Brad Witt. "If this accusation proves to be true, it's time for David Wu to resign and get the help he needs.

"These are deeply troubling accusations, and my thoughts are first and foremost with the young woman in question and her family," said another Democratic challenger, state Labor Commissioner Brad Avakian.