After the worst day of clashes in Gaza since it withdrew last summer, the Israeli military said its aircraft fired at four armed Palestinians on Friday.
Nearly 40 Palestinians have been killed since the offensive began last week, the military's chief said.
Lieutenant General Dan Halutz, in a military briefing broadcast on Israel Radio, said: "The terrorists have paid a heavy price so far."
Israel started its offensive on June 28 in an attempt to free Corporal Gilad Shalit, captured on June 25 by Palestinian fighters in Gaza.
There was still no word on the fate of the soldier.
Dozens of Palestinian casualties including women crowded the emergency rooms and corridors of Gaza hospitals, already suffering from shortages of medical supplies because of an Israeli closure of the territory after the soldier's capture.
After touring Gaza's main hospital on Thursday evening, Ismail Haniya, the Palestinian prime minister called for international intervention to stop the Israeli offensive, which he called a "crime against humanity".
" [The offensive was] a desperate effort to undermine the Palestinian government under the pretext of a search for the missing soldier"
Palestinian prime minister
Haniya said the offensive was "a desperate effort to undermine the Palestinian government under the pretext of a search for the missing soldier".
Call to arms
Said Siyam, the interior minister, meanwhile issued the Palestinian government's first call to arms since the Israeli invasion. He urged the security forces to fulfill their "religious and moral duty to stand up to this aggression and cowardly Zionist invasion."
The security forces are dominated by officers loyal to the rival Fatah Party, and there was no immediate response to his appeal.