Six Palestinians from the armed wing of the militant group Hamas have been killed in an Israeli incursion into the Gaza Strip, Palestinian officials say.
Recent days have seen the worst violence in Gaza in months
Israeli tanks entered northern Gaza near the town of Jabaliya overnight and Palestinian militants confronted them.
The Israelis say they are trying to stop missiles being fired on Israeli towns from the Gaza Strip.
Nineteen Palestinians, most of them militants, have died in Israeli attacks in Gaza over the past few days.
Meanwhile, the home of a prominent Palestinian militant was destroyed by an Israeli air strike in the southern Gaza town of Rafah on the border with Egypt.
Israel issued a warning before the strike and no one was killed or injured, says the BBC's Alan Johnston in Gaza.
An Israeli army spokeswoman told the French news agency AFP that the house "hid a tunnel used for arms smuggling."
The violence is the worst in the area since June, when the Israelis launched an offensive to try to rescue a captured soldier.
More than 220 Palestinians, many of them civilians, have been killed since then; two Israeli soldiers have been killed, one by "friendly" fire.
Three Israelis were wounded on Friday from crudely-made Palestinian missiles launched from Gaza at the nearby Israeli town of Sderot.
A spokesman for the Hamas-led Palestinian government denounced the latest Israeli operation.
Israel said this home belonged to a Palestinian militant
Ghazi Hamad urged the international community to "impose a sanction on Israel to stop their crime, their massacres against our people."
The Palestinians have also been suffering under an international aid boycott since Hamas was elected to a majority of seats in January's parliamentary poll.
Principal international donors, including the United States and the European Union have boycotted the Palestinian government over Hamas' refusal to recognise the Jewish state or to renounce violence.
Attempts to form a government of national unity between Hamas and President Mahmoud Abbas's more moderate Fatah faction have so far foundered on the recognition issue.