Photographs from Gaza show the extent of the destruction. Here is just one.

This article describes in detail the wreckage.

By Saturday morning, after a day of intense Israeli bombing and shellfire, the hospital in the northern Gaza town was standing in a sea of rubble, its walls pockmarked with gunfire and torn by shrapnel.

The skyline, until so recently regular and neat, had been transformed into something torn and ragged. The tops of a pair of minarets had been blown off, and the graves in a cemetery smashed to pieces. Houses, offices, apartment blocks and shops were collapsed or collapsing.
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What happened here in Beit Hanoun, and in other neighbourhoods of Gaza hardest hit by the Israeli assault, will inevitably demand an explanation: whether the extremity of violence unleashed in these residential areas in recent days was proportionate, or if the destruction amounts to a war crime.
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In the midst of an area of rubble the size of two football pitches in the last of these areas, we meet three brothers standing on what was once the four-storey building in which their families lived in four apartments. Next to them is a bomb crater measuring 10 metres across and six metres deep.

Alaa Helou, 35, a carpenter, points to what is no longer there. “That was a two-storey house. There was three storeys and over there was four storeys high. We came to see our house. We thought it might have been damaged by a shell. But there is nothing left of it.”

“We spent 20 years making our place nice,” says his older brother. “We spent all of our money on our homes.”

Even hospitals and ambulances have been hit.

At the nearby hospital, six patients and 33 medical staff had spent the night huddled in the X-ray department as the neighbourhood was shelled, said the director, Bassam Abu Warda. A tank shell had hit the second floor of the building, leaving a gaping hole, and the facade was peppered with holes from large-calibre bullets.

Two Red Crescent ambulances were hit in Beit Hanoun overnight, killing a medic and wounding three, one critically, according to the International Committee of the Red Cross. On Saturday, rescue workers pulled the scorched body of the medic from the wrecked vehicle, which had been hit about 200 metres from the hospital.

“Targeting ambulances, hospitals and medical workers is a serious violation of the law of war,” said Jacques de Maio, head of the ICRC delegation for Israel and the occupied territories.

Can there be any doubt that such actions would be condemned as war crimes by the US were it done by anyone other than the Israel or another client state/ally? How long before the claims of self-defense are seen as hollow?