Israel's defence ministry has ordered an inquiry into the killing of a Palestinian family in Gaza on Saturday.
Funerals of those killed in the strike were held on Sunday
Three generations of the family died when their car was caught in a missile blast during an attack on a militant.
The militant, Mohammed al-Dahdouh of Islamic Jihad, who was in a separate vehicle, was killed in the air strike.
At the funeral, a man who survived the attack said he had lost the greatest things in his life - his wife, his son and his mother.
MID-EAST DEATH TOLL: 2006
Palestinian militants or participating in violence: 66
Palestinian civilians: 39
Israeli civilians: 12 in Israel (including 4 foreign workers), 5 in the West Bank
Israeli soldiers: 0
(Based on B'tselem data, updated: 15 May)
His three-year-old daughter suffered severe injuries, and is in hospital in Gaza City, with her spinal cord severed.
Doctors say she will never be able to move her arms or legs again, and will need a machine to help her breathe for the rest of her life.
Many mourners at the funeral demanded attacks against Israelis to avenge the deaths of Naima Amen, her daughter Hanan and grandson Mohanad, AFP news agency said.
"Our response will make the ground tremble at the heart of the Zionist entity," an Islamic Jihad leader said in an address to mourners.
The cars were hit during the evening rush hour
Israel has acknowledged that the three were innocent victims but says the strike on Dahdouh was justified.
"We acted only after waiting a long time for the right occasion," Air force chief Eliezer Shkedi told AFP.
Islamic Jihad said Mohammed al-Dahdouh was one of its senior engineers involved in weapons manufacture.
The missile was apparently fired from an unmanned plane into the city centre during the evening rush hour.
The Israeli army has struck at militant targets in this way many times before, our correspondent says.
The strikes form part of their effort to stop militants from firing rockets into Israeli territory.
For their part, militants often say their attacks are in retaliation for Israeli military action in both Gaza and the West Bank.
Human rights groups have criticised what Israel calls the "targeted killing" of Palestinian militants, describing them as extra judicial killings. They have also pointed to the high risk such operations pose to civilians.
The British government on Monday condemned the killings on Saturday.
A statement said that while the UK welcomed Israel's decision to investigate the incident, it urged Israel to take all necessary steps to ensure that such a tragedy did not happen again.