GAZA CITY — An Israeli bomb pummeled a home deep into the ground here Sunday afternoon, killing 11 people, including nine in three generations of a single family, in the deadliest single strike since the cross-border conflict between Israel and the militant faction Hamas escalated on Wednesday.

An Israeli soldier worked at his tank at the Gaza border as the Israeli Army got ready for an operation on Sunday.

The airstrike, along with several others that killed civilians across this coastal territory and hit two media offices here — one of them used by Western TV networks — further indicated that Israel was striking a wider range of targets.

Gaza health officials reported that the number of people injured here had nearly doubled to 600 by day’s end; the Palestinian death toll climbed to 70, including 20 children. Three Israelis have been killed and at least 79 wounded by continued rocket fire into southern Israel and as far north as Tel Aviv, as Israeli cities were paralyzed by an onslaught of relentless rocket fire out of Gaza for the fifth straight day.

In the Israeli strike on Sunday morning, it took emergency workers and a Caterpillar digger more than an hour to reveal the extent of the devastation under the two-story home of Jamal Dalu, a shop owner. Mr. Dalu was at a neighbor’s when the blast wiped out nearly his entire family: His sister, wife, two daughters, daughter-in-law and four grandchildren ages 2 to 6 all perished under the rubble, along with two neighbors, an 18-year-old and his grandmother.

“We were asleep and then there was a terrific blast,” said Abdul-Latif Dahman, who lives nearby and was among more than 100 who stood vigil as the bodies were dug out. “There are no words to describe what happened later, only smoke and dust and heavy silence because the sound shut our ears.”

The smell of bomb residue and the roars of bulldozers filled the air as people clambered over shattered glass and bent iron bars to get a closer look. When two tiny bodies were finally found, rescuers and residents erupted in cries of “God is great!” One worker rushed the girl to an ambulance, while a neighbor grabbed the boy and just ran.

Ismail Haniyeh, the prime minister of the militant Hamas faction that rules Gaza, condemned the attack as a “massacre” that “exceeded all expectations.”

Brig. Gen. Yoav Mordechai, chief spokesman for the Israeli military, said it was “examining the event.”

“The wanted target in this case was responsible for firing dozens of rockets into Israel,” he added. “I do not know what happened to him, but I do know that we are committed to the safety of the citizens of Israel.”

Momentarily lulled by a quiet night, Israelis awoke Sunday to a new blitz of Palestinian rockets that totaled nearly 100 by nightfall, including two that soared toward the population center of Tel Aviv but were knocked out of the sky by the so-called Iron Dome missile defense system.

One rocket crashed through the roof of an apartment building in Ashkelon, a few miles up the coast from Gaza, where residents escaped serious injury because they had heeded the warning siren and run to lower floors. Four people were injured, two of them seriously, when a rocket exploded near their car in Ofakim, and a firefighter in Nachal Oz was seriously hurt by shrapnel.

A barrage of 10 missiles rained on Ashdod; nine were intercepted and the 10th hit an eight-story building but did not explode, heightening fears as residents were told to remain inside.

The whole region was paralyzed as people huddled in bomb shelters, where many have been spending the night. Malls were closed; few walked in the street.

“I am the kind of person that always checks where the bathrooms and the exits are,” said Carol Erdheim, a psychologist who lives in Ashdod and works in Ashkelon. “Now you look for where the safe room is. You just know what to do. It is a way of living.”

In Beersheba, an Israeli city of about 200,000 east of Gaza, Tal Rotem, a musician and father of three, said his family had not been leaving the house, “not even to shop.” A reservist in the Army’s southern command, Mr. Rotem is one of those on standby.

“My 5-year-old, Ori, said he did not want me to go because I could die,” Mr. Rotem said.

Sharon Galili, a lawyer who has 3-year-old twins and a 5-year-old, drove to his office in Ashdod but after 90 minutes and four or five rocket alerts sent his staff home and returned to his family in the village of Aseret.

“The children are terrified,” he said. “Every noise they hear — a truck or motorcycle — they ask if there is an alert. You feel their fear. We are not right-wing or left-wing; we just want quiet. The situation is surrealistic, but that is the reality we live in.”

There are no warning sirens here in the Gaza Strip, where the wee hours of Sunday were punctuated by airstrikes as well as by a series of missiles fired from Israeli Navy vessels off the coast.

Later in the morning, Mutassim Essifan, 5, and his 1-year-old sister, Jumana, were killed in the Jabiliya Refugee Camp near the northern border, followed by another baby in the Al Buraj Refugee Camp mid-strip and, by lunchtime, a 52-year-old woman in the eastern part of Gaza City. Ahmed Al-Nahal, 24, a member of Hamas’s military wing, and his relative Tasnim, 8, were killed before lunchtime in the Beach Refugee Camp, where Prime Minister Haniyeh lives.

Among the buildings Israel hit overnight were two containing the offices of local media outlets, in what the military described as an attempt to derail Hamas communications. The Israeli Air Force also briefly took control of Hamas’s radio network Sunday, broadcasting a message to Gaza residents. “Hamas is playing with fire and risking you,” it warned. “We recommend that you stay away from the places of terrorists and the infrastructure of Hamas.”

Ayman Amar, a spokesman for Al Quds television, said seven camera operators and editors were resting on couches in their 11th-floor offices in the Shawa and Hossari building in downtown Gaza City when a missile from an Israeli helicopter ripped through the roof at 1:30 a.m. All seven were injured, one losing a leg below the knee, Mr. Amar said, but they escaped before three more bombs dropped 10 minutes later.

“This will not deter us from showing the truth to the world,” he declared, as colleagues cleared the rubble. “We will not stop. It is our duty toward our cause to support the Palestinian people.”

Salama Marouf of the Hamas media office called the attack “an immoral massacre against the media,” and the Jerusalem chapter of the Foreign Press Association lodged a protest; several international outlets, including Fox News, Sky News, CBS and Germany’s ARD television, used production studios in the two targeted media buildings.

Israel’s vice prime minister, Moshe Ya’alon, who is in charge of strategic affairs, told reporters that the strike “didn’t intend to target journalists,” and that he had asked the military to investigate. “The attack helicopters were to hit Hamas military antenna — that was the target, not journalists.”