JERUSALEM — Israel and Hamas went back and forth Sunday over proposals to continue a humanitarian cease-fire in Gaza, but the Israeli military said it was resuming its aerial, naval, and ground combat because of Hamas’s “incessant rocket fire throughout the humanitarian window.”
Hamas, the militant group that dominates Gaza, called for a new 24-hour pause Sunday, hours after Israel had declared the end to its own cease-fire following a barrage of rocket attacks into its territory. That daylong cease-fire, requested by the United Nations, was to have lasted until midnight Sunday.
In a subsequent vote at an emergency meeting early Monday, the UN Security Council called for an ‘‘immediate and unconditional humanitarian cease-fire.’’
Some Israeli politicians, however, have begun talking about the possibility of escalating the offensive against Hamas and other Palestinian militant groups, which entered its 20th day Sunday, as intense international efforts during the weekend to press for an immediate, broader cease-fire appeared to have failed.
Huge clouds of smoke could be seen from the eastern neighborhoods of Gaza City that run close to the border with Israel, and fewer Palestinians were out on the streets Sunday than had been a day before.
A Hamas official in Gaza said it would observe a 24-hour cease-fire out of respect for Eid al-Fitr, the Muslim holiday that ends Ramadan. But Sunday afternoon, sirens wailed in Israeli communities close to the border, warning of incoming rocket or mortar shells from Gaza.
Israeli prime minister, Benjamin Netanyahu, said on CNN’s “State of the Union’’ that “Hamas doesn’t even accept its own cease-fire. It’s continuing to fire at us as we speak.”
Hamas wants to break the seven-year blockade of Gaza and believes the only way to force serious negotiations on ending the closure is to keep fighting. Israel wants more time to destroy Hamas’s rocket arsenal and military tunnels and to inflict enough pain to deter the Islamic militant group from launching rocket attacks.
US Secretary of State John Kerry spent several days in the region last week to seek agreement on an immediate weeklong truce during which talks on a new Gaza border deal would begin, but Israel’s Cabinet rejected the idea, in part because it would have meant calling off tunnel demolitions.
In a phone call Sunday, President Obama told Netanyahu the United States is growing more concerned about the rising Palestinian death toll and the worsening humanitarian conditions in Gaza. The White House said Obama reiterated that Israel has a right to defend itself and condemned Hamas rocket attacks that have killed Israelis, but pushed for an immediate cease-fire.
The 20-day war has killed more than 1,030 Palestinians, mainly civilians, and wounded about 6,000, the Associated Press reported, citing the Palestinian health ministry. Hundreds of houses have been destroyed in the Gaza Strip.
The ministry said that at least 10 people were killed by Israeli fire Sunday and that three more died from wounds they had sustained. Around the time that Israel called off its truce in the morning, two Palestinians believed to be militants were killed in a strike as they rode on motorbikes east of Khan Younis.
An Israeli reserve soldier was killed overnight by mortar fire from Gaza as he waited in a staging area along Israel’s border, according to the military, bringing the number of Israeli soldiers killed to 43 since the campaign began on July 8. Three civilians in Israel have also been killed by rocket and mortar fire.
An Israeli airstrike killed one person in Gaza when it hit a vehicle carrying municipal workers on their way to fix water pipes, the Palestinian Red Crescent said.
Police said Israeli tanks fired shells on densely populated areas south of Gaza City. One shell hit an apartment building and several shells struck a building. Navy boats also resumed firing on Gaza’s coast, police said. The Israeli military said it hit some 40 sites throughout Sunday.
In southern Israel, one person was injured and a house was damaged by a rocket launched from Gaza, Israeli police said. The Israeli military said more than 50 rockets were fired Sunday.
Also Sunday, the Israeli military acknowledged firing a mortar shell that hit the courtyard of a UN school in Gaza last week but said the yard was empty at the time and the shell could not have killed anyone, the AP reported.
Palestinian officials have said three Israeli tank shells hit the school in Beit Hanoun on Thursday, killing 16 and wounding scores. The school served as a shelter for Palestinians displaced by the fighting.
Lieutenant Colonel Peter Lerner, an Israeli army spokesman, said Sunday a military investigation determined that ‘‘a single errant mortar landed’’ but that it was ‘‘extremely unlikely that anybody was killed as a result of this mortar.’’
More than 160,000 displaced Palestinians have sought shelter at dozens of UN schools, an eight-fold increase since the start of Israel’s ground operation more than a week ago, the United Nations said. Hamas and other militants in Gaza have fired more than 2,400 rockets at Israel, many toward major cities.
Israeli airstrikes have destroyed hundreds of homes, including close to 500 in direct hits, according to Palestinian rights groups.
Lerner repeated Sunday that Israel would “continue to operate against the tunnels” and said that the pause in militant rocket fire on Saturday had proved that Hamas was able to control fighters in Gaza.
Atai Shelach, a former commander of the combat engineering unit in the Israeli military, told reporters in a telephone briefing that the only way to deal with the problem of the tunnels was to have soldiers in Gaza. He said Israel had discovered up to 40 tunnels and scores of access points and had destroyed several of them.
“We are in the middle of the operation,” he said, adding, “We won’t find all of them, and once we go out, they will start digging again.”
While Hamas said it was responding to the United Nations and was taking the needs of Gaza’s residents into consideration in seeking a new cease-fire, Netanyahu was facing political pressure from partners in his governing coalition and from some ministers within his own party not to take the pressure off Hamas.
Naftali Bennett, leader of the right-wing Jewish Home party, issued a statement on his Facebook page on Sunday morning saying: “Israel stands at a historic decisive moment. It is possible to defeat Hamas decisively and to dismantle its rockets and tunnels.”
He contended that Israel was winning the conflict and that with the Israeli public united in support of the operation, this was no time for a cease-fire that would allow Hamas to regroup. Addressing Hamas, he added: “No cease-fires, no lulls, no discussions. You have our phone number. When you are ready to demilitarize, call us.”
Shaul Mofaz, a centrist member of the Israeli Parliament and a former defense minister, told Ynet, a leading Hebrew news site, on Sunday that Israel had enough troops inside Gaza and stationed along the border to take the ground operation to “the next stage.”Material from the Associated Press was used in this report.