WASHINGTON — Rep. Charles Rangel announced today he will temporarily step down as chairman of the powerful House Ways and Means Committee, saying he didn't want his ethics controversy to jeopardize election prospects for fellow Democrats.

The 20-term Harlem congressman held a news conference on short notice, telling reporters, "My chairmanship is bringing so much attention to the press, and in order to avoid my colleagues having to defend me during their elections, I have this morning sent a letter" asking House Speaker Nancy Pelosi "to grant me a leave of absence until such time as the ethics committee completes its work."

The 79-year-old Rangel's decision was another jarring setback for President Barack Obama and majority Democrats in Congress, coming at a time when the party is scrambling to save sweeping health care overhaul legislation that has been pending on Capitol Hill for well over a year and still assessing a surging anti-incumbent fervor among the voters.

Republicans had been calling for Rangel to step aside since last year, when the House ethics panel expanded its investigation into his trips, assets and income, use of rent-controlled apartments in New York and his solicitation of contributions for university center to be named after him. After the panel released its findings last Friday on the Caribbean trips, Rangel started losing support among rank-and-file Democrats as well.

His departure from the Ways and Means chairmanship raised questions about succession.

Rep. Fortney "Pete" Stark of California is the most senior Democrat on Ways and Means, but there's no certainty that Pelosi would name him to fill in for Rangel. Stark chairs the panel's health subcommittee.

Other senior Democrats on the committee include Reps. Sander Levin of Michigan, Jim McDermott of Washington, John Lewis of Georgia and Richard Neal of Massachusetts.

Rangel is tied with Rep. Bill Young, a Florida Republican, for fourth place in congressional seniority.