Two Palestinian militants have been killed by Israeli troops launching an overnight raid in the Gaza Strip, Palestinian officials have said.
Eleven Palestinians, including several civilians, have been killed in Israeli operations Gaza in the last 24 hours.
The latest Israeli incursion comes as US President George W Bush prepares to visit Israel to give a push to Israeli-Palestinian peace talks.
Israel launches frequent raids on Gaza to stop rockets being fired at Israel.
The two militants killed early on Friday were from the Islamist movement Hamas. They were killed fighting Israeli troops near the town of Beit Hanoun in the northern Gaza Strip.
Thursday's fighting began when Israeli tanks and troops moved into the area close to Khan Younis in the southern Gaza Strip, sparking exchanges of fire with militants.
Five members of the same family, two of them militants from Islamic Jihad, were killed when a tank shell struck their house.
At least two other people were killed when Israeli airplanes launched strikes to help troops that were reported to have become trapped in one area.
In a separate exchange of fire in Gaza City, Hamas reported one of its gunmen was killed.
Schoolchildren were reported injured by Israeli fire on Thursday
Israeli troops also made an incursion into Nablus in the West Bank on Thursday and there were clashes in the centre of the city.
At least 19 people were injured, mostly young stone-throwers hit by rubber bullets.
At least six people were killed in pre-dawn strikes in Gaza on Wednesday.
The latest fighting is some of the heaviest seen in recent weeks.
Israel says it is trying to stop rocket fire into Israel. A rocket launched on Thursday reached the city of Ashkelon, some 17km (10 miles) north of Gaza.
No-one was hurt, but the Israeli army said it was the furthest a rocket launched from Gaza had reached.
It comes days before US President George W Bush visits the region to try to promote a peace agreement, in the last year of his administration.
Gaza is run by Hamas, which took over the territory last June after a violent struggle with its Fatah rivals.
Hamas is deemed a terrorist group by the US, and was not invited to the Annapolis conference organised by Washington in November, which kick-started the renewed attempt to agree a peace deal.