A House investigative panel formally charged longtime Rep. Charles Rangel with 13 ethics violations Thursday, setting the stage for a politically thorny trial months before the midterm elections.

In a 40-page statement of charges, a bipartisan panel said the New York Democrat had improperly solicited donations for a public center and library bearing his name and that he omitted hundreds of thousands of dollars of income and assets on disclosure statements.

The broad allegations had previously come to light over the course of the committee's nearly two-year investigation into Rangel's conduct, but the detailed charges and the start of a public trial came as lawmakers prepared to go home to meet with voters during the summer recess.

"One of the most difficult tasks assigned to a member of Congress is to sit in judgment of a colleague," said Rep. Gene Green, D-Texas, who led the four-member investigative panel. "The task is even more difficult when the subject of the investigation has befriended and mentored so many new members of Congress."

Rangel, 80, did not appear at the 30-minute hearing but instead submitted a lengthy statement in which his lawyers deny Rangel broke House ethics rules. The 20-term lawmaker said his lawyers are negotiating with the committee's staff to find an agreement to avoid a prolonged trial.

"The undisputed evidence is that ... Rangel did not dispense any political favors, that he did not intentionally violate any law, rule or regulation, and that he did not misuse his public office for private gain," the statement reads.