Get breaking news alerts and special reports. The news and stories that matter, delivered weekday mornings.

Several Democratic presidential candidates will skip the American Israel Public Affairs Committee's policy conference this year after a prominent progressive group called on them to boycott the event.

Sens. Elizabeth Warren, D-Mass., Kamala Harris, D-Calif., and Bernie Sanders, I-Vt., will all ditch the conference, the Associated Press reported, and a spokesman for former Rep. Beto O’Rourke, D-Texas, told NBC News that he also will not attend.

Pete Buttigieg, the mayor of South Bend, Indiana, will not be going, The Jewish Week reported, and former Secretary of Housing and Urban Development Julian Castro also won't show, according to HuffPost.

Former Starbucks CEO Howard Schultz, who is considering running for president as an independent, will also skip the conference, the Associated Press reported.

Josh Orton, a policy director for Sanders, told NBC News that the senator is "concerned about the platform AIPAC is providing for leaders who have expressed bigotry and oppose a two-state solution.”

Let our news meet your inbox. The news and stories that matters, delivered weekday mornings. This site is protected by recaptcha

Sanders didn't attend the 2016 conference while he was running in the Democratic presidential primary, but addressed the Israeli-Palestinian conflict at length during a speech around the time of the event.

The candidates' decisions to skip the prominent pro-Israel lobbying group’s conference come one day after liberal group MoveOn.org called on all 2020 presidential candidates to steer clear of the event.

“It’s no secret that that AIPAC has worked to hinder diplomatic efforts like the Iran deal, is undermining Palestinian self-determination, and inviting figures actively involved in human rights violations to its stage,” Iram Ali, campaign director for MoveOn's political action committee, said in a post on the group's website. “We asked our members what they think so that we can make more informed decisions — and over 74% agreed that progressive presidential candidates should skip the AIPAC conference. This should also give a clear insight to 2020 candidates on where their base stands instead of prioritizing lobbying groups and policy people who rarely step outside of D.C.”

AIPAC spokesman Marshall Whittmann said the "focus for the conference has always been Congress."

"We are proud that the bipartisan leadership of the House and the Senate will be speaking," Whittmann told NBC News.

Presidential candidate Sen. Elizabeth Warren, D-Mass., at an event in Las Vegas on Feb. 17, 2019. John Locher / AP file

Headliners at this year’s conference, which will kick off Sunday, include Israeli Prime Minister Benjamin Netanyahu and a number of prominent Democrats, such as House Speaker Nancy Pelosi, D-Calif., and Senate Minority Leader Chuck Schumer, D-N.Y.

AIPAC has been at the center of headlines about the Democratic Party in recent weeks, after Rep. Ilhan Omar, D-Minn., tweeted several controversial claims about Israel, including the claim that AIPAC was paying politicians to support Israel.

She was accused by some lawmakers and prominent Jewish groups of anti-Semitism and playing on toxic anti-Jewish stereotypes.

AIPAC, a nonprofit that does not donate directly to candidates but works to promote a staunchly pro-Israel message in Washington, responded to Omar, tweeting that it is "proud that we are engaged in the democratic process to strengthen the US-Israel relationship."

Omar later apologized after her comments were denounced by House Democratic leaders as "anti-Semitic tropes."