Israel’s conflict with the Palestinians intensified on several fronts as it grappled with communal riots in its cities and protests across the occupied West Bank while continuing to bombard Gaza, destroying a high-rise building housing international media.

As the number of Palestinians killed in Gaza rose to 136, including 55 women and children, the US and regional governments struggled to broker a ceasefire. Ten Israelis have been killed, including a child and a soldier.

Israel has rejected a second offer for a truce from Hamas, a western diplomat told the FT. Hady Amr, the US state department’s top official for Israel and Palestinian affairs was in Tel Aviv overnight, while the UN sought a two-hour halt to fighting on Sunday to ease the hostilities.

For a sixth day Israeli jets pounded the hemmed-in Gaza Strip, home to 2m Palestinians, and a woman and her four children were killed overnight when their home in a refugee camp was hit, local health officials said.

Israel’s prime minister Benjamin Netanyahu defended the relentless bombardment of the Gaza Strip, describing the campaign as a “just and moral war” that “is still not over and will continue as long as necessary”.

“We are doing everything, but everything, to avoid or limit as much as possible harming civilians,” he said. He was speaking after US president Joe Biden “raised concerns about the safety and security of journalists and reinforced the need to ensure their protection” in a phone call, according to a White House statement.

The bombing of the 11-story Al Jalaa residential and office block, used by US news agency Associated Press, and Al Jazeera was broadcast live by Al Jazeera, the Qatari satellite television network. The AP said it had received a warning to evacuate from the Israeli military.

“We narrowly avoided a terrible loss of life,” AP chair Gary Pruitt said. “They have long known the location of our bureau and knew journalists were there.” The Israeli military claimed the building was being used by a Hamas intelligence unit.

A statement by the White House reaffirmed Israel’s right to defend itself, but did not call for an end to its bombing campaign. Biden also spoke to Palestinian Authority president Mahmoud Abbas and “stressed the need for Hamas to cease firing rockets into Israel”, while reiterating US support for a two-state solution, the White House said.

Despite the Israeli bombardment, which has been ramped up to include artillery and tank fire, Hamas has fired about 2,500 rockets deep into Israel.

In the West Bank, Israeli security forces killed 11 Palestinians after angry protests erupted across the occupied territory on Friday, local health officials said.

Unrest in the West Bank could worsen significantly, an aide to the Palestinian Prime Minister Mohammad Shtayyeh told the FT, after nearly 80 demonstrations on Friday. Some turned violent with Palestinians throwing stones at Israeli soldiers.

The West Bank, which Israel has occupied since the 1967 war, is home to about 650,000 Jewish settlers, including at least 200,000 in East Jerusalem. The territory, which is the seat of Fatah, Hamas’s rival Palestinian faction, had been relatively quiet until Friday.

As well as its campaign against Hamas, Israel is struggling to contain the worst domestic violence in years as groups of Jews and minority Arab Israeli men have attacked each other’s communities and destroyed property in mixed Israeli towns.

Israeli police have arrested nearly 900 people as they attempt to stem riots in cities with mixed Jewish and Arab populations, with the communal strife exposing a deep rift within the Jewish state.

About 15,000 police officers battled to impose a night curfew in cities such as Lod, Haifa and Jaffa.

The Arab-Israeli conflict has for more than a decade been dominated by fighting between Israeli forces and Palestinian factions in the occupied territories. But the communal violence has sparked new tension.

Israeli Arabs account for about one-fifth of the Jewish state’s population, carry Israeli passports and vote in the country’s elections. But they say they suffer discrimination and their sympathy for the Palestinian cause has made them a target for rightwing Israeli politicians.

This week, Israel redeployed several thousand police from the West Bank to Israeli cities and towns as it stepped up efforts to stem the domestic unrest.

The crisis erupted after weeks of tension in and around Jerusalem, which escalated last week after police used rubber bullets, tear gas and stun grenades against Palestinian protesters in the compound of al-Aqsa mosque.

More than 600 Palestinians were wounded and images of the police using force against the protesters at Islam’s third holiest site — long a flashpoint in the Arab-Israeli conflict — inflamed Arab anger.

The al-Aqsa mosque lies in a compound — known to Muslims as the Haram ash-Sharif, or Noble Sanctuary, and to Jews as Temple Mount — that is sacred to both religions.

As tension escalated, Hamas entered the fray on Monday, firing rockets into Israel and demanding that Jewish settlers in Israeli-occupied East Jerusalem stop harassing Arab residents who were awaiting eviction orders from Israeli courts.

Israel responded by launching its biggest military campaign against Hamas since its 2014 war with the Islamist group.

Additional reporting by Katrina Manson in Washington