WASHINGTON — Democratic presidential hopeful Bernie Sanders announced Friday afternoon that he will not address the pro-Israel lobby AIPAC’s annual policy conference here — the only presidential candidate to skip the gathering.

In a letter to the president of AIPAC (the American Israel Public Affairs Committee), Sanders said he would have liked to appear, but would be unable to do so because of his campaign schedule.

“I would very much have enjoyed speaking at the AIPAC conference. Obviously issues impacting Israel and the Middle East are of the utmost importance to me, to our country and to the world,” wrote the Vermont senator to AIPAC’s President Robert Cohen. “Unfortunately, I am going to be traveling throughout the West and the campaign schedule that we have prevents me from attending.”

Sanders — who is Jewish — promised to send AIPAC the text of the speech he would have delivered, so that it can be distributed to the 18,000 participants at the conference, which runs Sunday to Tuesday, March 20-22.

“Since AIPAC has chosen not to permit candidates to address the conference remotely, the best that I can do is to send you a copy of the remarks that I would have given if I was able to attend,” he wrote. “We should be able to get that speech to you on Monday. Any help that you could give us in getting those remarks out to your members would be much appreciated.”

AIPAC has allowed presidential candidates to deliver speeches remotely in past elections. In 2012, Mitt Romney and Newt Gingrich, then candidates for the Republican presidential nomination, addressed the AIPAC conference via satellite. But AIPAC said Friday it was no longer the lobby’s practice to permit remote addresses.

“We invited the Senator and we gave him the same opportunity to speak as the other candidates,” an AIPAC official told JTA in an email. “We understand that he very much wanted to come but could not get back from West Coast to do it. We did change our policy and no candidate was offered/permitted the opportunity to address the conference remotely this year.”

Sanders’ decision to skip AIPAC was evidently a last-minute call, since the organization had still been waiting to hear from him at noon on Friday. The Sanders camp had initially responded with interest to an invitation to attend and address the confab, an insider told The Times of Israel. Sanders, trailing Hillary Clinton in the race for the Democratic nomination, faces contests in Utah, Idaho and Arizona on Tuesday.

All other presidential candidates will speak at the conference. Sanders’ Democratic rival, former secretary of state Hillary Clinton, will address the crowd Monday morning, while the three remaining Republican contenders — real estate mogul Donald Trump, Texas Sen. Ted Cruz and Ohio Gov. John Kasich — are scheduled to speak Monday evening. Vice President Joe Biden will also speak. A TV debate for Republican candidates was cancelled after Trump accepted AIPAC’s invite instead.

Sanders had received pressure in recent days not to speak at the policy conference, which will also be addressed, live by satellite from Israel, by Prime Minister Benjamin Netanyahu.

More than 5,000 people signed a petition orchestrated by anti-Israel activist Max Blumenthal urging Sanders to reject the invitation. Blumenthal’s father, Sydney Blumenthal, is a longtime confidant and adviser to Secretary Clinton, whose email correspondence with the Democratic frontrunner has been at the center of the controversy over her decision to use a private email server for official State Department communications.

Among the signatories of the younger Blumenthal’s petition are some prominent Sanders supporters, including musician and Pink Floyd founder Roger Waters.

Sanders, a Brooklyn-native and the first Jew to ever win a presidential primary, has been fairly quiet during the campaign regarding his views on Israel.

When he has expressed opinions and positions, however, they have been somewhat out of tune with AIPAC stances. He has spoken of a goal of less military and more economic US aid to Israel, vowed to be “evenhanded” in dealing with the Israeli-Palestinian conflict and supported the Iranian nuclear deal, which AIPAC worked fiercely against.

Throughout his senate career, Sanders has a record of voicing both support for and criticism of the Jewish state, including condemning Israel’s military response to intensified periods of conflict while simultaneously defending the country’s right to exist.

The AIPAC policy conference has made headlines recently over controversy related to the invite of Republican frontrunner Trump, which has stirred a heated debate in parts of the American Jewish community. Several rabbis are said to be planning to skip his speech, and some student activists have complained that AIPAC won’t let them protest his appearance. AIPAC has said publicly that all presidential candidates were extended an invitation, and noted that it has long maintained a policy of removing disruptive delegates.

Read: Where does Bernie Sanders stand on Israel?