Sanders is staying away from the annual conference of AIPAC, saying it offers a platform for "leaders who express bigotry and oppose basic Palestinian rights," and has denounced Netanyahu as a "reactionary racist."

Netanyahu, addressing the conference by satellite on the eve of Israeli elections, made a clear albeit unnamed swipe at Sanders, a leftist who would be the first Jewish US president.

"This year AIPAC was accused of providing a platform for bigotry. These libelous charges are outrageous," Netanyahu said.

Speaking to the thousands of AIPAC activists gathered at a Washington convention center, Netanyahu said: "You send a powerful message to all those who seek to weaken our great alliance that they will fail." 

Israeli Ambassador to the United Nations Danny Danon, a member of Netanyahu's Likud Party, was far more direct in attacking Sanders.

"We don't want Sanders at AIPAC. We don't want him in Israel," Danon said.

"Anyone who calls our prime minister a 'racist' is either a liar, an ignorant fool or both," Danon said.

Sanders lived on a kibbutz in Israel in the 1960s and calls himself a supporter of the Jewish state but has voiced alarm at its rightward turn.

Netanyahu has vilified Israel's Arab minority and vowed to annex much of the occupied West Bank if he secures another term in elections Monday -- the third time Israelis are voting in less than a year amid a political deadlock.

Calling the Palestinians "the pampered children of the international community," Netanyahu voiced confidence that the United States would recognize the annexation -- in line with a controversial Middle East peace plan presented a month ago by President Donald Trump, a staunch Netanyahu ally.

"This will be a truly historic day. The map of Israel will change, the future of Israel will change, and it will change for the better," he said.

LOS ANGELES, CA - MARCH 01: Presidential candidate Sen. Bernie Sanders holds a campaign rally at the Los Angeles Convention Center on March 1, 2020 in Los Angeles, California. Sanders is campaigning ahead of the 2020 California Democratic primary on Super Tuesday, March 3. (AFP/David McNew/Getty Images)

'Even-handed' Sanders 

Sanders, asked about AIPAC in a televised interview Sunday, promised to protect Israel's security but also to be more "even-handed."

"What we need in this country is a foreign policy that not only protects Israel but deals with the suffering of the Palestinian people as well," he said, deploring the 12-year blockade of the impoverished Gaza Strip.

Ex-military chief Benny Gantz, Netanyahu's centrist rival, did not mention Sanders in his own remarks by satellite to AIPAC but vowed to rebuild support for Israel in the United States.

"I will instill hope and not hate. That is the Israel we know; that is the Israel we need," Gantz said to applause.

"Israel will never, ever become a partisan issue," he said. "I will work effectively across both sides of the aisle."

While showing few gaps with Netanyahu on security issues, Gantz said he would oppose far-right politicians seeking to enter parliament and, in an issue important to many American Jews, promised inclusion at Judaism's holiest site, the Western Wall, where women are restricted.

NORFOLK, VIRGINIA - MARCH 01: Democratic presidential candidate former Vice President Joe Biden poses for selfies with supporters during a campaign event at Booker T. Washington High School March 1, 2020 in Norfolk, Virginia. After his major win in South Carolina, Biden continues to campaign for the upcoming Super Tuesday Democratic presidential primaries. (AFP/ Alex Wong/Getty Images)

Biden warns on annexation 

AIPAC for years has been an election-year rite of passage for candidates of each party, but only one Democratic contender plans to attend in person this time: former New York mayor Mike Bloomberg.

Former vice president Joe Biden, who was energized by a primary win Saturday in South Carolina, sent a video message in which he urged both Israelis and Palestinians not to scuttle a two-state solution.

He warned Israel not to move ahead with annexation and criticized the Netanyahu government's approval Thursday of nearly 1,800 new homes in the West Bank.

"That's going to choke off any hope for peace," Biden said.

"To be frank, those moves are taking Israel further from its democratic values, undermining support for Israel in the United States, especially among young people of both political parties. And that's dangerous," Biden said.

But while promising to speak his mind, Biden said, "I will never boycott you."

Fellow centrist Democratic contender Amy Klobuchar also sent a video message to AIPAC, while liberal Elizabeth Warren is skipping it.