Just before midnight on Thursday, Israeli tanks entered the Khan Yunus refugee camp in southern Gaza, witnesses said.
Helicopters fired two missiles, and the second wounded 12 people, hospital officials said.
Bulldozers tore down three houses across from a block of Jewish settlements.
The Israeli military said the purpose was to clear areas used by resistance fighters to fire at Israelis.
Early on Thursday, doctors said a 10-year-old girl, shot while in a Gaza classroom on 7 September, died of her wounds.
Local UN officials blamed Israel. The military said there were exchanges of fire with resistance fighters, but soldiers did not shoot at the school.