Palestinian security sources said a rocket fired by an Israeli aircraft took aim at a car, missed its target and struck a house.
Local medical sources and witnesses said 27-year-old Fatima al-Barbarawi was killed and 14 others were injured.
One of her relatives, Zakaria al-Barbarawi, 45, later died of wounds suffered in the attack.
The medical sources said that five children aged 1 to 4 were among the wounded and that of the 13 injured civilians four were in serious condition.
The Palestinian leadership condemned the strike, which came as the international community criticised the death of three Palestinian children in a raid on Tuesday.
Nabil Abu Rudeina, the Palestinian presidency spokesman, said: "The continued escalation and assassinations are exacerbating tensions in the region and compromise efforts seeking to relaunch the peace process."
Five children were injured in
On June 13, nine civilians were killed in an air raid, and on June 9, eight members of one family were killed while picnicking on a Gaza beach in an attack a rights group blamed on an Israeli shell.
Ryad Mansour, the Palestinian observer at the UN, appealed to the Security Council to demand that Israel, as an occupying power, abide by provisions of the fourth Geneva Convention, which he said were applicable to the occupied Palestinian territories.
The United Nations urged Israel to stop targeted killings of members of Palestinian resistance groups in the Gaza Strip.
Briefing the Security Council on the latest developments in the Middle East, Ibrahim Gambari, the UN undersecretary-general for political affairs, said Israel had stepped up its policy of targeted killings and of shelling Gaza areas from which rockets were fired at its territory.
He said Kofi Annan, the UN secretary-general, was "particularly disturbed that despite his prior expressions of concern, this pattern was repeated yesterday, when three children were killed and a number of bystanders injured, during another targeted killing by Israel".
"We would like to once again underscore the need for Israel to cease targeted killings, which continue to claim civilian lives"
UN undersecretary-general for political affairs
"We would like to, once again, underscore the need for Israel to cease targeted killings, which continue to claim civilian lives," Gambari said.
"It is the view of the secretary-general that Israeli actions should be proportionate and in accordance to humanitarian law."
Israel not dissuaded
But Israel said on Wednesday that it would not stop its policy of firing missiles at Palestinian targets despite the civilian deaths.
Major-General Eliezer Shakedi, Israel's air force commander, said air strikes remained the most accurate way to combat Palestinian fighters.
Shakedi told Israel's Army Radio: "We have to make a great effort to try everything possible to avoid hitting civilians. We have to fight terrorism and we are doing it ... this is more or less the central alternative, the most accurate and the best possible alternative without entering a broad and very significant [ground] operation."