Israel carried out more heavy airstrikes across Gaza city early on Monday, as an Israeli military official said a ground war was not off the table.
Explosions rocked the city from north to south for 10 minutes in an attack that was heavier, across a wider area and lasted longer than any of the raids in the preceding 24 hours.
Forty-two Palestinians were killed in the barrage, the latest round of violence between Israel and the Hamas militant group that controls Gaza.
Earlier air strikes demolished three buildings.
There were no immediate reports of injuries, and in the predawn darkness there was little detail on the extent of damage.
Local media reports said the main coastal road west of the city, security compounds and open spaces were hit.
The power distribution company said a line feeding electricity from the only plant to much of southern Gaza city was damaged.
Violence began in East Jerusalem last month, when Palestinians clashed with police in response to Israeli tactics during Ramadan and the threatened eviction of dozens of Palestinian families by settlers.
A focus of the clashes was the Al Aqsa Mosque, a frequent flashpoint located on a hilltop compound important to Muslims and Jews.
Hamas began firing rockets toward Jerusalem on Monday, triggering the Israeli assault on Gaza.
Rising death toll
At least 198 Palestinians have been killed in hundreds of air strikes on Gaza, including 58 children. Over 1200 people have been wounded, according to the Gaza Health Ministry.
Eight people in Israel were killed in some of the 3,100 rocket attacks launched from Gaza. They included a five-year-old boy and a soldier.
In a press briefing on Monday an Israeli military official said a ground war had not been "ruled out" at this point.
The official called the current fighting "a war of attrition" saying "the IDF can go on with this forever and they (Hamas) can go on with their rockets, sadly, also for a very long time."
Over the last week Israel's military has faced growing condemnation from around the world over the impact on the civilian population of Gaza.
Palestinian Prime Minister Mohammad Shtayyeh called on the international community to intervene in Gaza, calling the Israeli attacks a "systematic crime" and asking for the International Criminal Court to act swiftly.
Mr Shtayyeh also requested the facilitation of medical supply deliveries to the Gaza strip.
In a televised address on Sunday, Mr Netanyahu said Israel's attacks were continuing at "full-force" and would take time.
Israel "wants to levy a heavy price" on Hamas, he said, flanked by Defence Minister and political rival Benny Gantz in a show of unity.
Hamas also pressed on, launching rockets from civilian areas in Gaza toward civilian areas in Israel.
One hit a synagogue in the southern city of Ashkelon hours before evening services for the Jewish holiday of Shavuot, Israeli emergency services said.
No injuries were reported.
In the Israeli air assault early on Sunday, families were buried under piles of cement rubble and twisted rebar.
The hostilities have escalated over the past week, marking the worst fighting in the territory that is home to two million Palestinians since Israel and Hamas' 2014 war.
“I have not seen this level of destruction through my 14 years of work,” said Samir Al Khatib, an emergency rescue official in Gaza. “Not even in the 2014 war.”
Rescuers dug through the rubble with excavators and bulldozers. One shouted, "Can you hear me?" into a hole. Minutes later, a survivor was pulled out.
The Gaza Health Ministry said 10 children were among those killed, with more than 50 people wounded.
The Israeli army representative’s office said the strike was aimed at Hamas' “underground military infrastructure.”
As a result, "the underground facility collapsed, causing the civilian houses' foundations above them to collapse as well, leading to unintended casualties," it said.
Israel's air strikes razed some of Gaza city's tallest buildings, which Israel alleges contained Hamas military infrastructure. Among them was the building housing the Associated Press Gaza office and those of other media outlets.
Israeli military spokesman, Jonathan Conricus said at least 130 "enemy combatants" had been in strikes on 820 different targets, "mostly using the air force but not only,".
Hamas and the Islamic Jihad militant group have acknowledged 20 fighters were killed.
Israel said the number was far higher and released the names and photos of two dozen alleged operatives it said were "eliminated".
The Israeli military later killed Hasam Abu Harbid, Commander of the Northern Division in the Islamic Jihad terror organisation.
It said Abu Harbid was a commander in the group for over 15 years, and was behind several anti-tank missile attacks against Israeli civilians, including the attack from the first day of the current conflict in which a civilian was injured.
Islamic Jihad confirmed Abu Harbid's death.
Calls for calm and UN intervention
The assault displaced about 34,000 Palestinians from their homes, UN Mideast envoy Tor Wennesland told an emergency meeting of the UN Security Council, where eight foreign ministers spoke about the conflict.
Efforts by China, Norway and Tunisia to get the council to issue a statement, including a call for the cessation of hostilities, have been blocked by the US, which, according to diplomats, is concerned it could interfere with efforts to stop the violence.
"We have been working around the clock through diplomatic channels to try to bring an end to the conflict," US Secretary of State Antony Blinken said at a joint briefing with Denmark's foreign minister in Copenhagen on Monday.
"The United States remains greatly concerned by the escalating violence. Hundreds of people killed or injured, including children being pulled from the rubble," he said.
He said the US was ready to support if the parties wanted help to negotiate a ceasefire.
Palestinian Foreign Minister Riyad Al Maliki urged the UN Security Council to take action to end Israeli attacks.
Israel's UN ambassador, Gilad Erdan, called on the council to condemn Hamas' "indiscriminate and unprovoked attacks".
Turkey's President President Recep Tayyip Erdogan on Monday appealed to Pope Francis to help rally the world to adopt sanctions against Israel, and Russia