WASHINGTON - Rep. Charles Rangel, the most powerful tax-writing lawmaker in Congress and a 40-year veteran of Capitol Hill, acknowledged Thursday that an ethics panel has accused him of accepting corporate money for Caribbean trips in violation of House rules.

The findings are certain to raise questions of whether Rangel, a New York Democrat, can continue as Ways and Means Committee chairman in an election year. Democrats took over the House in 2006 on a campaign promise to "end a culture of corruption" in Congress that they blamed on 12 years of Republican rule.

The ethics panel also ended another widespread investigation Thursday, saying it found no violations of House rules by seven lawmakers who steered government money and projects and contracts to favored companies that donated to their re-election campaigns.

A copy of the letters and an accompanying report on them were obtained by The Associated Press. All seven - five Democrats and two Republicans - are or were senior members of the House Appropriations Committee.

The most prominent of the them was the late Rep. John Murtha, D-Pa., the former chairman of the defense appropriations subcommittee who died earlier this month. The other six lawmakers exonerated in that probe are Reps. Norman Dicks, D-Wash.; Jim Moran, D-Va.; Marcy Kaptur, D-Ohio; Peter Visclosky, D-Ind.; Todd Tiahrt, R-Kan.; and C.W. "Bill" Young, R-Fla.

The appropriations went to companies represented by a now-defunct lobbying firm known as PMA Group - formerly Paul Magliocchetti Associates.

The Justice Department was conducting an investigation of its own into PMA. It is unclear whether that inquiry is still alive. At one point, a federal grand jury subpoenaed documents from Visclosky's office, campaign committees and some of his employees. The chief of staff for the Indiana Democrat resigned after the subpoenas were delivered.

The House committee's report said its investigators "found no evidence" that members or their official staffs considered or sought contributions in return for appropriations.

The committee also found that PMA used "strong-arm" tactics, threatening to withdraw financial support or encourage businesses to leave a member's district if the lawmaker opposed appropriations to companies represented by the firm.

"In these instances, members and their staff refused to change their positions and, in one case, notified the (ethics) committee," the report said.