At least four Palestinians have been killed in two Israeli missile strikes in the southern Gaza Strip, Palestinian officials say.
Two family members died in one strike on a house in Rafah, hospital officials said. A second strike killed two men, said to be Islamic Jihad militants.
About a dozen Palestinians have died in the past three days of Israeli action.
Israel has carried out many operations in Gaza since the capture of one of its soldiers by militants in June.
The BBC's Lucy Williamson, in Gaza City, says the two who died in the strike on the house in Rafah were teenagers - a brother and his younger sister. Their mother was also seriously injured.
Doctors have spoken about many people turning up at the local hospital since the early hours of this morning with serious shrapnel wounds, our correspondent adds.
The Israeli army says it carried out three air strikes in the area overnight, all aimed at gunmen, some armed with anti-tank missiles.
After Israeli forces hit one of the gunmen, an army spokesman said there was a secondary explosion, suggesting he had been carrying explosives.
Dozens of Israeli tanks have been operating just outside Rafah since Thursday morning.
The army says it is looking for militants and the tunnel they used to kill and capture Israeli soldiers in June.
About 150 Palestinians, many of them civilians, have died in Israeli attacks in Gaza since the capture of Cpl Gilad Shalit.
The United Nations says 35 children have been killed in the past month alone.