At least seven Palestinian gunmen have been killed in fighting with Israeli forces in the Gaza Strip. Israel has stepped up an offensive aimed at stopping Palestinian rocket attacks and winning the release of a kidnapped soldier.

The Israeli army says clashes erupted in Gaza when Palestinian militants fired an anti-tank missile at a military bulldozer. Israeli troops responded with heavy fire from the air and the ground.

A house where Hamas gunmen were holed up took a direct hit, and they were killed. Palestinian officials identified the dead as members of the ruling Islamic militant group, Hamas.

Later, an Israeli aircraft fired missiles and destroyed a car in Gaza City. The army said it targeted gunmen from the Fatah faction, led by moderate Palestinian President Mahmoud Abbas.

It was third day of intensified fighting, in which armed militants have taken heavy casualties.

Israel stepped up its more than three-month-old offensive in Gaza, in an attempt to stop Palestinian rocket attacks during the week-long biblical holiday of Sukkot-the Feast of Tabernacles.

"I think it's incumbent upon us, upon the government of Israel, to act pro-actively to prevent them murdering Israelis," said government spokesman Mark Regev.

Israel, the United States and European Union regard Hamas as a terrorist organization, because it seeks the destruction of the Jewish state. Palestinian spokesman Ahmed Yousef says Israel is trying to bring down the Hamas-led government.

"They're trying to use all the military might they have to undermine the Palestinian cause, and putting us under the pressure," he said.

Israel says it is pressuring the Palestinian government to release an Israeli soldier, who was kidnapped by Hamas gunmen in a cross-border raid at the end of June. The army has launched almost daily raids into Gaza since then, but Hamas has refused to free the soldier, until Israel releases hundreds of Palestinian prisoners. So far, Egyptian efforts to mediate a prisoner swap have failed.