The allegations - which include failure to report rental income from vacation property in the Dominican Republic and to report more than $600,000 in assets on his congressional financial disclosure statements - came as lawyers for Rangel and the House ethics committee worked on a plea deal.
One was struck, people familiar with the talks said, but Republicans indicated it might be too late.
"Mr. Rangel was given multiple opportunities to settle this matter. Instead, he chose to move forward to the public trial phase," said Rep. Jo Bonner of Alabama, the senior Republican on the ethics panel.
The alleged violations of House standards of conduct also include using congressional letterhead to solicit donations for a center for public service to bear Rangel's name on the New York campus of the City College of New York.
Rangel was also accused of accepting a rent-stabilized property in Manhattan for his campaign office and initially not paying federal taxes on the Dominican Republic property.
The charges, agreed upon after a two-year probe, were read in a public session of the Committee on Standards of Official Conduct, as the ethics committee is formally known.
Rangel, 80, did not attend.
The session set the stage for a committee trial, expected to be held in September. Democrats had hoped to avoid such a public confrontation as November elections approach.
"We live at a time when public skepticism about the institutions in our country is very high," said Rep. Zoe Lofgren, D-Calif., the ethics committee chair.
She said it had been the panel's goal "to by our actions rebuild and earn trust by the public and our colleagues."
Republicans have been trying to turn the case into an indictment of Democratic leadership. Rangel stepped down earlier this year as chairman of the tax-writing House Ways and Means Committee, one of the top posts in the House.
But Bonner told colleagues, "No one, regardless of their partisan stripes, should rejoice."
"It is the duty of the House to punish its members for disorderly behavior. As such, this is truly a sad day," the Alabama Republican said.
Under the tentative plea deal, it was not immediately clear how many of the 13 charges of ethical violations Rangel agreed to accept.
The ethics panel that will judge Rangel's conduct held its first meeting Thursday.
It includes eight members, equally divided between Democrats and Republicans. Thus, for any deal to be accepted it must be approved by at least one Republican.
In the frantic hours leading up to the meeting, Rangel's lawyer, Leslie Kiernan, talked to attorneys for the panel about how to avoid a trial for the 40-year veteran.
Rep. Michael McCaul of Texas, the top Republican on the panel that will try Rangel, said that the Democrat had been "given the opportunity to negotiate a settlement during the investigation phase."
However, he said, that phase is now over. "We are now in the trial phase," he said.
A congressional trial could be avoided only if Rangel admitted to substantial violations, or resigned.
Punishment could range from a report criticizing his conduct to a reprimand or censure by the House, or a vote to expel him - which is highly unlikely. Any agreement would have to be approved by Rangel and ethics committee members.
"Sixty years ago I survived a Chinese attack in North Korea and as a result I haven't had a bad day since," Rangel told reporters earlier Thursday. "But today I have to reassess that statement."
House Speaker Nancy Pelosi was asked if she was worried about the potential election-year fallout for Democrats. "The chips will have to fall where they may politically," she said. Pursuing ethics cases against House members is "a serious responsibility that we have," she added.
"I think everyone is looking forward to getting all the facts out in the open, and people will have to react once we know what we're dealing with," said Rep. Mike Quigley, D-Ill.
Rangel is tied for fourth in House seniority. He's still vigorous at 80 years old.
He had substantial influence as Ways and Means chairman. The panel handles taxes, trade, portions of health care, Medicare and Social Security.
But he stepped down from that post in March after the ethics committee criticized him in a separate case, saying he should have known that corporate money paid for two trips to Caribbean conferences.
Rangel had repeatedly said he looked forward to a public discussion of the current allegations. A four-member investigating panel, with separate members from the judging subcommittee, brought the charges.
The 42-member Congressional Black Caucus has warned Democrats against a rush to judgment, and any lawmaker with a significant African-American constituency must consider whether it's worth asking Rangel to quit.
However, some Democratic House members in close races may think it's more important to distance themselves from Rangel. They don't want to have to answer negative Republican ads about Pelosi's promise to wipe Congress clean of ethical misdeeds.
Two Democrats didn't wait to hear the charges.
Rep. Betty Sutton of Ohio, a second-term lawmaker who received 65 percent of the vote two years ago, said Rangel needs to resign to preserve the public's trust in Congress.
Rep. Walt Minnick of Idaho, a freshman who got 51 percent of the vote last time, called for resignation if the charges are proven. Congress adjourns for its August recess after this week.
Associated Press writers Ann Sanner and Alex Brandon contributed to this report.