Relatives gathered at the hospital. Some wept as the body of a girl was placed in a white plastic bag and laid alongside the other bodies wrapped in thick blankets.

The "attack took us by surprise", said Ahmed al-Masri, who identified himself to AFP as a survivor of the strike. 

"I could hear the children crying out for help, yet I was unable to save them," he added.

"My brother's entire family was wiped from the civil registry: him, his wife and their four children."

He said he had helped his children escape through a window, while flames devoured the building.

Another witness, Youssef al-Masri, said the strike took place around 2:00am.

"While we were asleep, we heard the sound of a massive explosion and found that the house had been shelled, destroyed and engulfed in flames," he said.

The civil defence agency said six other people were killed on Tuesday in another Israeli strike in Gaza.