WASHINGTON — Oregon Democratic Rep. David Wu faced increased pressure today after House Democratic leader Nancy Pelosi called for an ethics investigation over an 18-year-old woman’s claim of an “unwanted sexual encounter” with him.

Pelosi issued a statement Sunday night calling on the House Ethics Committee to begin looking into the allegations against Wu.

Meanwhile, lawmakers will find it harder to avoid questions about their position on Wu’s future, a scenario similar to six weeks ago when they had to deal with the distraction of former Democratic Rep. Anthony Weiner, who had sent lewd photos of himself to women online. Unlike the media frenzy that ensued in the Weiner case, Wu’s situation has prompted little attention so far because of the intense focus on lawmakers’ struggle to reach a deal on raising the national debt ceiling.

Wu and Pelosi had a telephone conversation Saturday but neither politician has disclosed details.

Wu hasn’t spoken publicly about Pelosi’s statement.

The Oregonian, citing an unidentified senior Democrat official, said that Wu did not intend to resign but would complete his term and retire in 2012.