A prominent opposition leader and member of Israel’s war cabinet, Benny Gantz, is calling for early elections in September, echoing demands by the Senate majority leader in the United States, Chuck Schumer, as pressure grows on the government of Prime Minister Netanyahu.

“We must agree on a date for elections in September, towards a year to the war if you will,” Mr. Gantz said at a press conference on Wednesday. “Setting such a date will allow us to continue the military effort while signaling to the citizens of Israel that we will soon renew their trust in us.”

Mr. Netanyahu faces heightened turmoil both abroad and at home over his handling of the 134 Israeli hostages still held at Gaza six months into the war. “What Israel needs is quiet in the ballot box, not flames in the streets,” Mr. Gantz said. At a protest in Jerusalem on Tuesday, a protester threw a torch at a police cavalry officer and police officers used force against family members of hostages.

An election could bolster Mr. Gantz’s National Unity party, which is down to eight seats from the 12 it won in the last election, since the chairman of the United Right party, Gideon Sa’ar, broke away in March. Mr. Gantz has consistently passed 30 seats in recent polling, while Mr. Netanyahu’s Likud party, which currently has 32 seats, has failed to reach 20.

“When a leading member of Israel’s war cabinet calls for early elections and over 70% of the Israeli population agrees according to a major poll, you know it’s the right thing to do,” Mr. Schumer said in response to Mr. Gantz’s comments. In March, Mr. Schumer made a splash on the Senate floor when he described Mr. Netanyahu as preventing peace in the Middle East and called for elections to replace him when the war calms down. 

In response, Netanyahu told Senate Republicans that invading Rafah is necessary to defeat Hamas and criticized Mr. Schumer’s push for Israeli elections as “wholly inappropriate.”

Mr. Gantz, who joined Mr. Netanyahu in an emergency government days after the Hamas massacre in October, doubled down on his position that he would leave the government if it failed to act to return the hostages kidnapped by Hamas, though he declined to say whether he would quit if the prime minister did not accept his demand. “We will do everything for our proposal to be accepted. I will not detail what Netanyahu said in response,” he said.

Mr. Netanyahu, Israel’s longest-serving prime minister, has repeatedly rejected calls for early elections. He says that bringing voters to the ballot box in the middle of a war would only reward Hamas. “Elections now will bring about paralysis, division, harm to the fighting in Rafah and a fatal blow to the chances of a hostage deal,” his Likud party said on Wednesday.