GAZA CITY, Gaza Strip — Israeli forces killed at least 11 people, including several children, in a single airstrike that destroyed a home here on Sunday, as Israel pressed its bombardment of the Gaza Strip for a fifth day, deploying warplanes and naval vessels to pummel the coastal enclave.
The airstrike, which the Israeli military said was meant to kill a Palestinian militant involved in the recent rocket attacks, was the deadliest operation in the recent clashes and was expected to weigh on negotiations for a possible cease-fire.
Among the dead were five women and four small children, the Associated Press reported, citing a Palestinian health official. In all, 73 Palestinians, including 37 civilians, had been killed in the five-day onslaught. Three Israeli civilians had also died and more than 60 have been injured from Palestinian rocket fire.
Two Gaza media offices were also hit on Sunday, and Prime Minister Benjamin Netanyahu of Israel warned of a ‘‘significant’’ expansion in the offensive unless Hamas halted the rocket barrage.
On Monday, the Palestinian civilian death toll mounted as Israeli aircraft struck densely populated areas in the Gaza Strip in its campaign to quell militant rocket fire, the Associated Press reported. Overnight, an airstrike leveled two houses, killing two children and two adults and injuring 42 people, said Gaza heath official Ashraf al-Kidra. A missile strike on a pickup truck killed three members of the radical Islamic Jihad group, said Hamas security officials.
Cease-fire talks began in Cairo on Sunday, but both sides were digging in, officials close to negotiations said.
An emboldened Hamas made sweeping demands, including the permanent opening of the border crossing between Gaza and Egypt and the end of the Israeli blockade.
Hamas, badly outgunned on the battlefield, appeared to be trying to exploit its increased political clout with its ideological allies in Egypt’s new Islamist-led government.
Even as the diplomacy intensified, the attacks continued in Gaza and Israel. Palestinian militants fired more than 100 rockets into Israel on Sunday.
Speaking on Sunday from Bangkok, President Obama condemned missile attacks by Palestinian fighters in Gaza and said that Israel had a right to protect itself.
‘‘There’s no country on earth that would tolerate missiles raining down on its citizens from outside its borders,’’ Obama said in his first public comments since the violence broke out. ‘‘We are fully supportive of Israel’s right to defend itself.’’
The president also said that efforts were underway to address Israel’s security concerns and end the violence. ‘‘We’re going to have to see what kind of progress we can make in the next 24, 36, 48 hours,’’ he said.
Militants in Gaza aimed at least one rocket at Tel Aviv on Sunday, a day after Israeli forces broadened the attack beyond military targets, bombing centers of government infrastructure in Gaza, including the four-story headquarters of the Hamas prime minister.
“We are exacting a heavy price from Hamas and the terrorist organizations,’’ Netanyahu told his cabinet at its Sunday meeting.
His remarks were reported shortly after a battery of Israel’s Iron Dome defense shield, hastily deployed near Tel Aviv on Saturday in response to the threat of longer-range rockets, intercepted at least one aimed at the city on Sunday, Israeli officials said. It was the latest of several salvos that have illustrated Hamas’s ability to extend the reach of its rocket attacks.
Since Wednesday, when the escalation of the conflict began, Iron Dome has knocked 245 rockets out of the sky, the military said Saturday, while 500 have struck Israel.
The US-financed system is designed to intercept only rockets streaking toward towns and cities and to ignore those expected to strike open ground. But on Sunday a rocket fired from Gaza plowed through the roof of an apartment building in the southern Israeli city of Ashkelon. There were no immediate reports of casualties there.
In Gaza City, the crash of explosions pierced the quiet several times throughout the early morning. A Hamas militant was killed and seven people were wounded in an attack on the Beach Refugee Camp, where Ismail Haniyeh, the Hamas prime minister, has a home. Those killed included three children ages 1 through 5, the health officials said.
Talks continued in Cairo that President Mohammed Morsi of Egypt said Saturday night could soon result in a cease-fire. Netanyahu said he would consider a comprehensive cease-fire if the launchings from Gaza stopped.
The attack on Haniyeh’s office, one of several on government installations, came a day after he hosted his Egyptian counterpart in the same building, a sign of Hamas’s new legitimacy in a radically redrawn Arab world. That stature was underscored Saturday by a visit to Gaza from the Tunisian foreign minister and trips to Cairo by two Hamas allies, the prime minister of Turkey and the crown prince of Qatar, for talks with the Egyptian president and the chairman of Hamas on a possible cease-fire.