WASHINGTON — Representative Ilhan Omar, who has been battling charges of anti-Semitism for weeks, apologized on Monday for insinuating that American support for Israel is fueled by money from a pro-Israel lobbying group — a comment that drew swift and unqualified condemnation from fellow Democrats, including Speaker Nancy Pelosi.

The mea culpa by Ms. Omar, a freshman lawmaker from Minnesota and one of the first two Muslim women elected to Congress, came after a day of bipartisan outrage over her tweet Sunday night asserting that support for Israel was “all about the Benjamins baby,” a reference to hundred-dollar bills.

“Anti-Semitism is real and I am grateful for Jewish allies and colleagues who are educating me on the painful history of anti-Semitic tropes,” Ms. Omar said in a statement released on Twitter, about an hour after Ms. Pelosi and the entire Democratic leadership publicly chastised her for engaging in “deeply offensive” anti-Semitic tropes.

The verbal altercation between Ms. Pelosi and Ms. Omar was only the latest example of the speaker stepping in to try to keep her diverse and unruly caucus in line. She finagled her own election to the speakership, threw some subtle cold water on Representative Alexandria Ocasio-Cortez’s ambitious “Green New Deal” and tamped down aggressive talk of impeaching President Trump. In the coming days she may again have to step in to pass an immigration and border security deal that is likely to anger the most liberal wing of the House.

But even as Democrats in Congress condemned Ms. Omar, her fierce and persistent criticism of Israel is exposing tensions within the broader party, with younger liberals increasingly willing to accuse the Jewish state of human rights abuses while older stalwarts like Ms. Pelosi stand firmly behind it. Republicans, sensing an opportunity to woo Jewish voters, have sought to exploit those divisions, and on Monday evening, Mr. Trump weighed in.

“I think she should be ashamed of herself,” the president told reporters, referring to Ms. Omar. “I think it was a terrible statement and I don’t think her apology was adequate.”

At the same time, Ms. Pelosi is facing questions from Republicans in Congress about whether she went far enough. When Representative Steve King, Republican of Iowa, made comments embracing white supremacy, Representative Kevin McCarthy of California, the Republican leader, stripped him of his committee assignments and the House passed a resolution condemning his words.

Mr. McCarthy, who was accused of anti-Semitism himself this fall when he said the billionaires George Soros, Michael R. Bloomberg and Tom Steyer were trying to buy the election, has demanded that Ms. Pelosi do the same with Ms. Omar. She serves on the House Foreign Affairs Committee — a plum assignment that puts her in a position to influence American policy in the Middle East.

So far, the speaker has declined to take that action, but she did coordinate the condemnation of Ms. Omar’s words from the top five House Democratic leaders.

“Legitimate criticism of Israel’s policies is protected by the values of free speech and democratic debate that the United States and Israel share,” the five said in their joint statement, in which they called on Ms. Omar to immediately apologize. “Congresswoman Omar’s use of anti-Semitic tropes and prejudicial accusations about Israel’s supporters is deeply offensive.”

Ms. Omar’s Twitter comment linking money from the American Israel Public Affairs Committee, or Aipac, to political support in Washington for Israel played into anti-Semitic tropes that have their roots in the Middle Ages, when Jews were barred from entering most professions and thus became moneylenders — a task that Christians would not take on because of prohibitions against usury.

That fueled centuries of stereotypes about Jews using money to control the world. Rabbi Jonah Pesner, director of the Religious Action Center of Reform Judaism, drew an analogy between Ms. Omar’s comments and those who make light of blackface without understanding the hateful history of minstrel shows and how they were used to dehumanize African-Americans.

“What she doesn’t realize is Aipac, like every other advocacy organization in Washington, is exercising its constitutionally protected rights to advocate on behalf of its agenda,” Rabbi Pesner said, adding, “When you call it out and differentiate the Jewish community, it feeds that stereotype of controlling the world.”

In her Twitter statement on Monday, Ms. Omar did not back away from her contention that Aipac has too much power in Washington. “At the same time, I reaffirm the problematic role of lobbyists in our politics, whether it be Aipac, the N.R.A. or the fossil fuel industry,” Ms. Omar wrote.

Critics of Israel say Ms. Omar has a point. In separate interviews on Monday, both Emily Mayer, the national coordinator of IfNotNow, a liberal Jewish group, and Yousef Munayyer, the director of the U.S. Campaign for Palestinian Rights, said Ms. Omar was forcing an important discussion in Washington.

“Twitter is probably not the best medium for nuanced conversation,” Mr. Munayyer said. “But I don’t think the correct answer is we can’t talk about it. I think it is very important in this moment to have a conversation about U.S. relations with Israel.”

Ms. Mayer said she “wholeheartedly” accepts Ms. Omar’s “apology for her word choice while also appreciating the moral stance that she takes on this issue, which is pretty unprecedented in today’s Congress.”

Monday’s back and forth came on top of earlier flash points that pitted Ms. Omar against Israel’s fiercest supporters in Congress, Republican and Democrat. She told Yahoo News last month that when politicians “still uphold” Israel “as a democracy in the Middle East, I almost chuckle.” That brought back criticism of a 2012 tweet in which she accused Israel of hypnotizing the world to mask its evil deeds.

She had been trying to mend fences over those comments when Sunday night’s tweet went viral.

Before the leaders’ statement on Monday, other Democrats had broken rank to voice their condemnations. Two House Democrats, Representatives Elaine Luria, a freshman from Virginia, and Josh Gottheimer of New Jersey, released a letter Monday morning calling on Democratic leaders to speak out against any lawmaker who “uses harmful tropes and stereotypes, levels accusations of dual loyalty or makes reckless statements like those yesterday.”

“As Jewish members of Congress, we are deeply alarmed by recent rhetoric from certain members within our caucus, including just last night, that has disparaged us and called into question our loyalty to our nation,” they wrote. “We urge you to join us in calling on each member of our caucus to unite against anti-Semitism and hateful tropes and stereotypes.”

The two said in interviews that they were referring both to Ms. Omar and to another freshman Democrat, Representative Rashida Tlaib of Michigan, the other Muslim woman in Congress. Ms. Tlaib has also drawn fire for remarks that her critics say fuel anti-Semitic tropes, and Ms. Luria and Mr. Gottheimer recently met with her to express their concerns.

Both said they left the meeting disappointed that she did not apologize. Ms. Tlaib, who is Palestinian-American and whose grandmother lives in the West Bank, responded with a statement Monday evening saying in part that her “life’s work is centered on equality and justice,” adding, “I am not easily bullied away from choosing peace and truth dialogue.”

Other Democrats also weighed in. Representative Jerrold Nadler of New York, the chairman of the House Judiciary Committee, called it “deeply disappointing and disturbing to hear Representative Ilhan Omar’s (MN) choice of words in her exchange with a journalist yesterday, wherein she appears to traffic in old anti-Semitic tropes about Jews and money.”

But he also chastised reporters at the Capitol for not taking Mr. McCarthy, the Republican leader, to task for saying Jewish philanthropists and political donors were buying the election, comments that he saw as anti-Semitic. “Their caucus stayed united and had his back and none of you called him out,” he said.

The Twitter exchanges began when Ms. Omar responded to a tweet by the journalist Glenn Greenwald. Mr. Greenwald had accused Mr. McCarthy of targeting Ms. Omar and Ms. Tlaib.

That’s when Ms. Omar said, “It’s all about the Benjamins baby.”

It did not end there. A Jewish journalist asked whom Ms. Omar was referring to when she suggested that money was driving American policy on Israel. “AIPAC!” she replied. Aipac does not contribute to political campaigns, but its large-scale conferences and congressional trips to Israel have long drawn enthusiastic and bipartisan participation.

They have also elicited charges that Aipac has deliberately fed a one-sided view of the Israeli-Palestinian conflict into American politics and squelched any alternative perspectives. Ms. Tlaib has been trying to organize her own congressional trip to the West Bank to give lawmakers the Palestinian side of the issue.

Aipac responded with a statement that said: “We are proud that we are engaged in the democratic process to strengthen the U.S.-Israel relationship. Our bipartisan efforts are reflective of American values and interests. We will not be deterred in any way by ill-informed and illegitimate attacks on this important work.”

A version of this article appears in print on , on Page A1 of the New York edition with the headline: After Backlash, Democrat Rues Tweet on Israel. Order Reprints | Today’s Paper | Subscribe