Prime Minister Benjamin Netanyahu of Israel assailed Senator Chuck Schumer on Wednesday in a closed-door speech to Senate Republicans, days after the Democratic majority leader branded him an impediment to peace in the Middle East and called for a new election to replace him after the war winds down.
Mr. Netanyahu’s virtual appearance at a weekly gathering of Republican senators — and a refusal by Mr. Schumer to allow him to make a similar address to Senate Democrats — dramatized the growing partisan split on Capitol Hill and in American politics over Mr. Netanyahu’s leadership and Israel’s offensive in Gaza.
“Senator Schumer made it clear that he does not think these discussions should happen in a partisan manner,” said Alex Nguyen, a spokesman, explaining why the senator had declined a request by Israeli officials to have the prime minister address Democrats at their weekly closed-door lunch as well. “That’s not helpful to Israel.”
Inside the meeting with Republicans, Mr. Netanyahu called Mr. Schumer’s speech last week on the Senate floor “wholly inappropriate and outrageous,” according to Senator Josh Hawley, Republican of Missouri, who attended. And many Republican senators spoke up to say they agreed with him.
“He was not happy,” Mr. Hawley said of the prime minister. “He made that very clear.”
In an explosive speech last week, Mr. Schumer listed Mr. Netanyahu alongside Hamas as one of the major impediments to peace, and tried to lay out the case that Americans can love and support Israel and still be deeply critical of Mr. Netanyahu and his far-right government.
President Biden called it a “good speech” and some Democrats applauded Mr. Schumer for speaking out at a moment when Israel’s offensive against Hamas has resulted in tens of thousands of deaths in Gaza, including civilians. But conservative Jewish groups and Republicans were stunned and dismayed, and accused Mr. Schumer of crossing a dangerous line.
Former President Donald J. Trump went even further, saying in an interview that Jews who vote for Democrats “hate Israel” and their religion. It was an extreme version of a tactic many elected Republicans have long attempted, portraying Democrats who question Mr. Netanyahu or his policies as denouncing Israel itself and even being antisemitic.
His appearance at Wednesday’s closed-door G.O.P. confab was not the first time that Mr. Netanyahu has waded into a bitter partisan struggle over support for Israel, allying himself with Republicans eager to showcase their backing for the Jewish state. In 2015, the prime minister accepted an invitation by House Republicans to make his case to Congress against the Iran nuclear deal, without consulting the White House then in the throes of negotiating the deal.
On Wednesday, Mr. Netanyahu told Republicans on Capitol Hill that his policies reflect the consensus of Israelis and that Mr. Schumer’s remarks would have no bearing on how he planned to move forward with his offensive.
“He made it very clear that he intends to prosecute the war against Hamas to the full extent of his power, and he said the American people are behind him,” Senator John Kennedy, Republican of Louisiana, said. “He said that even if we have to go alone, we will not stop.”
Senator Mitch McConnell, Republican of Kentucky and the minority leader, said he conveyed to Mr. Netanyahu that he believed Mr. Schumer had crossed a line in “giving a democratic ally advice about when to have an election or what kind of military campaign they should be conducting.”
“It seems to me the bipartisan support for Israel seems to be cracking,” Mr. McConnell said, making it clear that he thought the Democrats were responsible.
Senator Christopher S. Murphy, Democrat of Connecticut, said on Wednesday night that Mr. Netanyahu was trying to play off the parties against each other.
“If Netanyahu is upset at Schumer or other Democrats for speaking the truth, getting cozier with Republicans and infusing more partisanship into Israel’s relationship with America is definitely not the answer,” he said.
In his speech last Thursday, Mr. Schumer accused Mr. Netanyahu of pursuing policies that undermine Israel’s own democratic values and endanger the possibility of a two-state solution in the future. He has accused Republicans of politicizing support for Israel, which in the past was always bipartisan and blamed Mr. Netanyahu for only catering to Republicans.
In the meeting, Mr. Netanyahu asked Republicans to continue their vocal support for Israel and to allow it to finish the war, according to multiple attendees.
“He emphasized several times that Israel is not asking for American ground troops, not asking America to fight its war,” Mr. Hawley said. Mr. Netanyahu did ask for financial help to “finish the job” and urged senators to support whatever bill the House sent them that included billions of dollars in aid for Israel.
Mr. Hawley said Republicans asked Mr. Netanyahu directly for numbers on the civilian death toll in Gaza. “He was very mindful of it, he talked about it at some length,” Mr. Hawley said, noting that Mr. Netanyahu assured them the Israelis were making every effort to minimize civilian casualties. He said he estimated the death toll to be about 28,000, about 2,000 fewer than the Gaza Health Ministry has said.
Mr. Schumer on Wednesday defended his address, amid a flood of accusations that he was interfering in the democratic process of a close ally.
“I gave the speech out of a real love for Israel,” he said. “If you read the speech, we called only for there to be an election after the hostilities have declined, after Hamas was defeated.”
Republicans made it clear they planned to continue to hammer him for his address and to blame Democrats for the growing partisan divide over support for Israel.
“Schumer doesn’t have to like or dislike Benjamin Netanyahu on a personal level,” Senator Ted Cruz, Republican of Texas, said. “Schumer’s attack was directed at the people of Israel, because it’s the people of Israel who went and voted. Chuck Schumer had the arrogance and audacity to seek to instruct another nation as if it were a vassal state, a banana republic.”
Robert Jimison contributed reporting.