Gaza City - Khader Khader had less than one minute to evacuate his home.

At 7am on Friday, the 55-year-old was sleeping under the staircase with his five children, when he heard his neighbour scream, "Dr Khader, evacuate! They are going to bomb my house!"

At that moment, Khader's seven-year-old son, Mohammed, tucked his tiny fingers into his father’s trousers and froze, unable to move. Quickly getting everyone out of bed, the family ran out of the yellow villa - which Khader spent years saving money to build and only moved into two years ago - just as the first Israeli missile, a warning shot, screeched by.

"We ran anywhere we could, away from the house so as not to get hurt or killed," Khader recalled, his voice shaking.

They crammed into the car and reached the top of the street before the second missile, fired from an Israeli F-16, hit the neighbourhood. Khader's home was not the target, but his neighbour's house was. "My children are traumatised from the bombing - what did they do to deserve this?" Khader, a respected university professor of linguistics, said.

My children are traumatised from the bombing - what did they do to deserve this? - Khader Khader, 55, father of five

His children, aged between seven and 16, have yet to return to see the damage. "The trauma is so immense, that they fear coming back to their home, where we escaped by a miracle," he told Al Jazeera.

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At the same time the Khader family’s home was bombed, another house in Rafah, in southern Gaza, was hit by Israeli missiles. The Ghannam family received no warning and five people were killed in their sleep, while another 16 were injured.

At least 154 Palestinians have been killed and almost 1,000 others injured as Israel's military operation continued into a sixth day on Sunday. At least 70 Palestinian homes have been completely destroyed, according to the United Nations, while another 2,500 housing units have sustained minor damage.

Israeli Prime Minister Benjamin Netanyahu said on Wednesday: "Hamas will pay a heavy price for firing at Israel's citizens."

On Twitter, the Israeli army has defended its operation, accusing Hamas of hiding rockets and other weapons in "houses, mosques, hospitals [and] schools" and of operating "deep within residential areas". The military has argued that it has made efforts to minimise civilian casualties, but said that houses can be considered lawful military targets.

But the UN has said that even if a home is being used for military purposes, "any attack must be proportionate, offer a definite military advantage in the prevailing circumstances at the time, and precautions must be taken".

Jaber Wishah, deputy director of the Palestinian Human Rights Center (PCHR) in Gaza City, said that Israel has engaged in the "punitive destruction" of Palestinian homes in Gaza. "Those houses - even if they belong to a Hamas [member] or Islamic Jihad [member] - they should be considered civilian objects. They did not participate in the military operations," he said.

Wishah told Al Jazeera that there are three scenarios that usually occur before Israel bombs a home in Gaza. The army may carry out an air strike without any prior warning, it may fire a warning shot - known as "roof-knocking", a dud missile will land on the roof of a house to alert the inhabitants that the real missile is on its way - or it may call Palestinian families to tell them to evacuate before they bomb their homes.

"Every single home in Gaza is within the target circle," Wishah said. "No place is safe in Gaza now. Each home could be a target, either directly or indirectly affected."

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Back in Gaza City early Friday morning, Khader returned to his home to survey the damage. His neighbours were also out to examine the rubble. "It’s like after a tsunami," said a reporter on the scene.

Only the frame of the house is still standing; the family's personal possessions are destroyed, furniture is broken, shrapnel litters the floors of every room, and not a single door or window is intact. His personal collection of books, photographs, and letters is also gone.

Khader didn't manage to save anything from his home, not even identification papers. As he inspected the destruction, still in a state of shock, another Israeli air strike struck nearby. Children ran screaming from the next house, where they were collecting clothes and toys.

"Out of all this, there is nothing that I can use," Khader said, as he stumbled around his home. "The loss is too great."

Follow Mohammed Omer on Twitter. Jillian Kestler-D'Amours contributed reporting.