GAZA CITY — 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 to date and would no doubt 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.
Two media offices were also hit on Sunday, and Prime Minister Benjamin Netanyahu of Israel warned of a “significant” expansion in the onslaught, which has already killed over 50 people, many of them civilians.
Speaking on Sunday from Bangkok, President Obama condemned missile attacks by Palestinian fighters in Gaza and defended Israel’s right to protect itself.
“There’s no country on earth that would tolerate missiles raining down on its citizens from outside its borders,” Mr. 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 under way 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,” Mr. Obama said.
Even as the diplomacy intensified on Sunday, the attacks continued in Gaza and Israel.
Mr. Netanyahu made his warning as militants in Gaza aimed at least one rocket at Tel Aviv, 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, and the Israel Defense Forces are prepared for a significant expansion of the operation,” Mr. Netanyahu told his cabinet at its routine Sunday meeting, referring directly to the of thousands of reservists who have been called up and the massing of armor on the Gaza border that many analysts have interpreted as preparations for a possible invasion.
“I appreciate the rapid and impressive mobilization of the reservists who have come from all over the country and turned out for the mission at hand,” Mr. Netanyahu said. “Reservist and conscript soldiers are ready for any order they might receive.”
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 American-financed system is designed to intercept only rockets streaking toward towns and cities and to ignore those likely 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.
Before the latest deadly strike involving civilians on Sunday, Hamas health officials had said the Palestinian death toll had risen to 53. One of the latest victims was a 52-year-old woman whose house in the eastern part of Gaza City was bombed around lunchtime.
A few hours earlier, a Hamas militant was killed and seven people were wounded in an attack on the Beach Refugee Camp, where Ismail Haniya, the Hamas prime minister, has a home. Those killed on Sunday included three children ages 1 through 5, the health officials said.
In Israel, 3 civilians have died and 63 have been injured. Four soldiers were wounded on Saturday.
The onslaught continued despite talks in Cairo that President Mohamed Morsi of Egypt said Saturday night could soon result in a cease-fire. Mr. Netanyahu said he would consider a comprehensive cease-fire if the launchings from Gaza stopped.
The attack on Mr. Haniya’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.
