Updated

In the second botched Israeli airstrike in Gaza in two days, two people were killed and 13 were wounded when a missile hit a house Wednesday, just hours after grieving and angry Palestinians buried three children killed in a previous attack.

Militants vowed revenge, and Israelis debated the effectiveness of airstrikes that target militants but are taking a mounting toll on innocent Palestinians.

In Wednesday's attack, Israeli aircraft targeted militants in the southern Gaza city of Khan Younis but hit a house instead, killing a man and a woman and wounding at least 13 people, including five children, according to hospital officials.

CountryWatch: Israel

The dead woman was identified as Fatma Abdel Khader, 35. The man, visiting from Saudi Arabia, was identified as Zakaria Ahmed, 45.

The missile blew a hole in a wall of the one-story concrete block shack. A pool of blood covered part of the kitchen floor of the stricken house.

A witness said a car carrying Palestinian militants passed the house as the missile struck. They jumped from the car and ran into a nearby field.

A senior air force officer, speaking on condition of anonymity under military regulations, said the missile missed its target by several dozen yards.

Israel says its strikes are aimed at militants involved in daily rocket fire from Gaza against Israeli towns. The high civilian toll is stirring a debate inside Israel, with critics saying the airstrikes serve only to inflame militant passions. Targeting rocket launchers in crowded Gaza is particularly problematic during the summer, when tens of thousands of children play in the streets.

Two 5-year-olds and a 16-year-old were killed in an airstrike Tuesday.

On Wednesday, a mother collapsed in grief and an elderly man kissed a poster of his dead grandson as they buried their children.

The oldest of the three dead was Bilal al-Hassi, 16. The Fatah movement of Palestinian President Mahmoud Abbas put up posters of the teen, calling him a "martyr."

"If they had an inch of religion, they would not have done that, not right in the middle of people," said the youth's 65-year-old grandfather, Hassan Ghandoor.

Falestin al-Sharif, mother of 5-year-old Samia al-Sharif, said her daughter had gone to get a sandwich for her disabled aunt when she was killed. The mother said she would like to become a suicide bomber to avenge her daughter's death.

"If I get my hands on an explosive belt, I would go and explode myself inside Israel to tear their hearts out for their children, like they did to me," she said.

Feeda Roka, 16, whose 5-year-old brother, Mohammed, also was killed Tuesday, likewise pledged revenge. "All Palestinians will avenge Mohammed's blood," she said.

Their funeral procession was filled with anguish and anger.

A militant grabbed a microphone and asked the crowd, "Do you want a cease-fire?" and the mourners shouted back, "No!" He was referring to a shaky February 2005 truce declared by major Palestinian militant groups, including Hamas, which earlier this year took over the Palestinian parliament and Cabinet.

Militant groups pledged to increase their rocket attacks against Israel, targeting the town of Sderot, just outside Gaza's border fence.

Abu Qusai of the Al Aqsa Martyrs' Brigades, linked to Fatah, said flatly, "We will not commit to the truce." Referring to civilian deaths in earlier incidents, he added, "How can we hear the cries of these children, like the ones on the beach of Gaza, and stand idle?"

On June 9, eight Gaza beachgoers were killed in a beach blast Palestinians blamed on an Israeli artillery shell. Israel claimed it was not responsible.

On Wednesday, the military said examination of another fragment removed from the body of a wounded Palestinian receiving treatment in Israel backed up that conclusion.

Since the outbreak of the latest Palestinian uprising, or intefadeh, in 2000, Israel has killed dozens of militants in missile attacks, but hundreds of bystanders have been killed and wounded as well.

At least eight Palestinian civilians were killed in a separate Israeli airstrike last week, which came just a few days after the beach explosion.

Israeli critics questioned the wisdom of targeting militants in heavily populated areas.

Ran Cohen, a retired army officer and a lawmaker from the dovish Meretz Party, said even when Israel succeeds in killing militants, "the damage is far greater than the gain."

International criticism was quick and harsh. British Foreign Minister Margaret Beckett condemned Tuesday's airstrike, saying, "The killing of innocent civilians, and particularly children, is completely unacceptable."

Palestinians and human rights groups reject the airstrikes as summary executions.

But Israel's leaders insisted they would step up their attacks to try to stop the rocket barrages, targeting leaders of militant groups. "We shall take tough measures, tougher and more frightening than those we took in the past," Prime Minister Ehud Olmert said Tuesday.

The botched air raids overshadowed the first tentative move toward renewed peace negotiations following Hamas' victory in parliamentary elections in January.

U.N. Secretary-General Kofi Annan urged Israel to stop targeted attacks that have killed dozens of Palestinian civilians and called on the Palestinians to stop firing rockets on Israeli territory.

A statement from the secretary-general's spokesman deplored the killing on Tuesday of three Palestinian children and called on Israel "to respect international law and to ensure that its actions are proportionate and do not put civilians at grave risk."

On Wednesday night, an explosion in a car near Palestinian security headquarters in Gaza City injured a security official and two other people, witnesses and medics said.

Palestinian security said the injured official was Yasser Dahlan, a cousin of Gaza Fatah kingpin, Mohammed Dahlan. Also wounded was Yasser Dahlan's mother-in-law, who was in the vehicle, and a security guard.

A local Fatah spokesman said it appeared that an explosive device had been planted in the car.

Mohammed Dahlan is one of the most powerful Fatah figures in the volatile Gaza Strip but has no official position since the radical Islamic Hamas took over the government after ousting Fatah in parliamentary elections in January.