JERUSALEM — President Biden for the first time expressed support for a cease-fire between Israel and Hamas militants in Gaza on Monday, as the devastating rocket and missile war there gave no sign of easing after the deaths of dozens of Palestinian children.
But he also reiterated that Israel had a right to defend itself, stopping short of publicly calling on Israel to change its approach despite rising international condemnation.
The statement, issued after Mr. Biden spoke with Israeli Prime Minister Benjamin Netanyahu, was the furthest that Mr. Biden had gone toward calling for an end to the conflict. But it also reflected a continued and deep reticence by world leaders to criticize Israel, and a failure of diplomacy to persuade the two sides to curb a rising cycle of violence.
For their part, Israel’s leaders have said that they are in no hurry to end the airstrike campaign and have insisted that the military will continue until it reaches its goals of stopping Hamas’s rocket barrages and making the group “pay a price.”
“The directive is to continue striking at the terrorist targets,” Mr. Netanyahu said on Monday after meeting with Israeli security officials. “We will continue to take whatever action necessary in order to restore quiet and security for all the residents of Israel.”
Over eight days, Hamas has fired nearly as many rockets — 3,350 so far — as it did over all of the 50-day conflict between Israel and Hamas in 2014, and has killed nine civilians in Israel, including two children, and at least one soldier.
But in Gaza, Palestinian families have paid a much greater price. Since May 10, at least 212 Palestinians had been killed in Gaza, including 61 children, according to health officials there, and many have been left homeless. Gazan officials said that more than 600 homes or businesses had been destroyed and more than 6,400 damaged, and United Nations officials said that at least 800,000 Gazans lack regular access to safe drinking water.
Though civil unrest by Palestinians and Arab citizens of Israel had quieted down in recent days, a general strike and demonstrations have been called for Tuesday afternoon to protest Israel’s air campaign in Gaza and other measures targeting Palestinians, organizers said.
In Washington, Mr. Biden’s language was carefully couched. It notably avoided a demand that the cease-fire be “immediate,” language that Democratic senators used in a letter to the president earlier in the day.
It appeared to be an effort to press Israel to suspend its airstrikes — assuming Hamas also ended its barrage of rockets into Israeli cities — despite Mr. Netanyahu’s declaration that Israel would keep fighting until it had gravely reduced Hamas’s military capacity, including an extensive network of underground tunnels.
In the statement, the White House made clear that it expected others in the region to play a major role, saying Mr. Biden “expressed his support for a cease-fire and discussed U.S. engagement with Egypt and other partners toward that end.”
But he set no deadline and did not appear before cameras to make a public demand — just as he avoided making statements or taking questions during outings this weekend near his home in Delaware.
The Israeli military says it is focusing on airstrikes against the tunnel network because Hamas, which controls Gaza, uses the tunnels to move people, weapons and equipment around the coastal strip undetected. Referring to the subterranean transit system as the “metro,” Israeli officials say the air campaign against the network, which was years in the making, marks a new phase in the long battle between Israel and the militant groups.
Concern over the role of Gaza tunnel networks in attacks against Israelis was a rationale for the military ground invasion of Gaza in 2014, which caused huge loss of life.
Since then, Hamas has greatly expanded that network, according to Israeli intelligence officials. But they say the militants’ focus now is not on passages that reach all the way into Israel, but rather on the creation of shelters for Hamas commanders and fighters within Gaza — from 20 meters beneath the ground to as deep as 70 meters — and a sprawling transportation network for weapons and fighters.
An Israeli Air Force official, who briefed reporters on Monday on the condition of anonymity, in line with military rules, said that reinforced concrete tunnels ran for hundreds of miles inside Gaza. Israel was not trying to destroy it all, he said, but to create “choke points” that would seal sections off and make parts of the network inoperable.
But above ground, whole structures within Gaza are tumbling down or being scorched and blasted while the airstrikes continue.
At least seven Palestinians were killed in Gaza in Israeli strikes on Monday, officials said, including a man Israeli officials described as an important commander for the militant group Islamic Jihad. At least two civilians were reported killed when one strike hit an office building, Gaza officials said.
On Sunday, intense Israeli bombing made it the deadliest day yet for Palestinians, with at least 42 people killed, including at least 10 children, after an attack on a tunnel network caused three buildings to collapse.
Raji Sourani, of the Gaza-based Palestinian Center for Human Rights, said that the main effect of Israel’s bombardment has been to terrorize Gazan civilians and ruin their homes and businesses. He called Israeli bombardment of the tunnels in recent days “meaningless” given the network’s scale.
“They want the civilians to revolt against the resistance,” he said, referring to provoking a public Palestinian uprising against Hamas rule. “And this is not going to happen.”
Since the underground tunnel system is clandestine, Hamas officials are evasive when asked about its existence, let alone how badly it has been hit or whether operatives have been trapped inside by the Israeli bombardments over the past week.
“It is the right of the resistance to possess all types of weapons and means to defend itself,” Abdel Latif al-Qanou, a spokesman for Hamas, said in an interview on Monday. “And tunnels are one of the means of self-defense.”
Palestinians in the Gaza Strip, the West Bank and Israel live under different governments and have increasingly developed separate identities. But leaders from across all three announced that they would stage a general strike on Tuesday to protest Israel’s air campaign in Gaza and other measures targeting Palestinians, organizers said.
The initiative also has the backing of both Hamas, and Fatah, the ruling party of the Palestinian Authority that exercises limited self-autonomy in parts of the West Bank.
“We want to send a clear message that we stand together in saying enough to the aggression on Gaza,” said Essam Bakr, one of the organizers. “But we are also saying enough to the attacks on the Aqsa Mosque, enough to the occupation and settlement-building, and enough to the unjust treatment of Palestinians.”
As the rocket and airstrike barrages have continued, Hamas has been vague about its calculations and goals. The group does not recognize Israel as a legitimate state, and the group has tried to establish itself politically as a forceful defender of the Palestinian people and Islamic holy sites, like the Aqsa Mosque in Jerusalem.
In the fighting, rockets have been Hamas’s go-to weapon, raining down on Israeli towns and cities at a much faster rate than in 2014. On Monday, Israelis rushed to shelters again, and rockets were reported to have hit in Ashdod, Ashkelon and Sderot. No one was reported killed in those strikes.
But Israeli officials say that the militants have also been trying surprise tactics, including sending drones loaded with explosives across the border. Those have been thwarted so far, officials say.
Hamas also tried to take to the sea on Monday, according to the Israeli military, with a naval unit suspected of preparing a “submergible naval weapon” for action. The military released a video showing Israeli forces destroying the vessel.
Mr. Netanyahu’s open-ended statements about the need to destroy Hamas’s capability have appeared to put Mr. Biden in a corner, which was reflected in the careful wording of the White House statement Monday.
In what amounts to the first Middle East crisis of his presidency, Mr. Biden wants to avoid the political risk of appearing to have his appeals ignored. But he also has little leverage over Israel, unless the United States is willing to threaten a cutoff of aid or arms — not politically likely at a moment that Hamas is firing rockets at Israeli citizens.
On Monday, the White House press secretary, Jen Psaki, told reporters that the administration would not reveal all the details of Mr. Biden’s communications with leaders in the conflict. “Our approach is through quiet, intensive diplomacy,” she said. “That is how we feel we can be most effective.”
It is a sharp shift from President Trump’s approach, embraced in the Middle East plan he issued a year ago. It was widely viewed as ignoring many of the Palestinians’ interests, in favor of Israel’s demands.
Earlier in the day, Secretary of State Antony J. Blinken, speaking to journalists in Copenhagen, said the Biden administration was “working intensively behind the scenes to try to bring an end to the conflict.”
He added, “We will immediately resume the work, the vital work, of making real the vision of Israel and a Palestinian state existing peacefully, side by side, with people from all communities able to live in dignity.”
Mr. Biden has been under intensifying pressure from prominent Democrats on Capitol Hill to more forcefully push for peace, as it has become increasingly clear the center of his party is shifting away from the kind of unflinching support for Israel’s prerogatives that has long been bipartisan.
After more than half of Senate Democrats, for instance, called for an immediate cease-fire in a statement Sunday night, half of the Jewish Democratic members in the House made a similar demand. They warned Mr. Biden that “the United States cannot simply hope and wait for the situation to improve.”
Reporting was contributed by Iyad Abuheweila from Gaza; Ronen Bergman from Tel Aviv; Adam Rasgon and Irit Pazner Garshowitz from Jerusalem; Gabby Sobelman from Rehovot; and Dan Bilefsky and Marc Santora from London.