The United Nations rapporteur on human rights in the occupied territories, Francesca Albanese, has said the aim of the Gaza City offensive is to make it uninhabitable. “This is the last piece of Gaza that needs to be rendered unliveable,” she said on Monday.

But the Israeli mission to the UN rejected her remarks, blaming Hamas for the destruction, Julian Borger has reported, while Benjamin Netanyahu defended Israel’s tactics. “We’re not bringing down those towers [in Gaza City] to intimidate people,” the Israeli prime minister said. “Those towers are serving as Hamas strongholds.”

The Israeli military’s chief of staff, Lt Gen Eyal Zamir, is widely reported to have deep misgivings about the Gaza City offensive, arguing it would not destroy Hamas and would be costly in the lives of Israeli soldiers and hostages.

Before today’s Israeli military actions, the Israel Defense Forces have been destroying blocks of flats across Gaza City and ordering its inhabitants to evacuate, drawing international condemnation, as Julian Borger has reported.

Tens of thousands of Palestinians have fled Gaza City for the south, but most of the estimated million people sheltering in the urban sprawl have opted to stay, either because they are unable to move or because they have nowhere to go.

Humanitarian agencies have said there is nowhere left in Gaza that is safe or suitable for displaced people, the report continues. The UN relief agency, Unrwa, said 10 of its buildings had been hit by Israeli strikes in the past four days, including seven schools and two clinics.

Palestinian residents have reported heavy strikes across Gaza City. One overnight strike hit a house in the western side of Gaza City, killing at least five Palestinians including two children, according to the Shifa hospital, which the received the bodies.

Another strike hit at least three houses in the south-western side of the city, the Associated Press reports residents as saying. Medics were searching the rubble for survivors. “It was a heavy night,” said Radwan Hayder, a Gaza City resident sheltering near the Shifa hospital. The Israeli military has not responded to questions for hours over whether the offensive has begun.