Palestinian mother Maleeha Awwad still cannot explain what happened the day her 14-year-old daughter stabbed a man with scissors and was shot dead by police.

As far as she knew, Hadeel had walked to school with her cousin Norhan, 16. Instead, the two girls went to Jerusalem's central market and carried out the attack.

Nearly a month later, Israeli authorities finally released Hadeel's body on Friday to enable the family to bury her.

"I still don't understand what happened," Awwad said at her home on the edge of the Qalandiya refugee camp near Ramallah, shaking her head and close to tears.

The United Nations and human rights groups have voiced concern that Israeli security forces are responding to alleged attacks with excessive force.

The Israeli police officer who shot the teenagers has been placed under investigation, the first such probe since a wave of violence began on 1 October.

Security camera footage from the incident on November 23 appears to show the two girls in school uniform chasing a man with scissors before being shot.

Police said the girls had stabbed and lightly wounded a 70-year-old Palestinian nearby, apparently mistaking him for a Jew.

The footage shows both girls shot and on the ground. The policeman runs back towards one of them, apparently Norhan, and opens fire despite her being curled in a ball.

Norhan was seriously wounded but survived. Shehas been charged with attempted murder.

Lawyers for the policeman have said he was concerned that the girls may have been wearing explosive belts.

Suicide bombings were common during the second Palestinian intifada between 2000-2005 but have not occurred in the current unrest.

'Extrajudicial executions'

At least 120 Palestinians and 17 Israelis have been killed in over two months of stabbing, shooting and car-ramming attacks by Palestinians, and in clashes between Palestinian youths and Israeli soldiers.

Over half of the Palestinians killed have been alleged attackers.

This week a UN spokeswoman voiced deep concern over the "unacceptable" wave of attacks, as well as "reports of excessive use of force by Israeli forces".

"The response from Israeli security forces has resulted in alleged attackers, protesters and even bystanders being killed and injured," said Cecile Pouilly, spokeswoman for the UN human rights office.

Amnesty International's Philip Luther welcomed the probe by the justice ministry as a positive development but warned that other cases did not appear to be getting the same treatment.

"The fact that this is the first such investigation into killings by police since ... October is deeply troubling, particularly given the strong indications that many Palestinians were killed when they were not posing an imminent threat to life or of serious injury," Luther said.

Earlier this year, Luther accused Israel of carrying out "extrajudicial executions".

The Israeli police dismissed the criticism.

"What does Amnesty understand about split-second decisions that police officers have to make when there is a terrorist holding a 30-centimetre knife in front of their face, just about to cut their throat?" police spokesman Micky Rosenfeld told AFP.

"Each attack is different, and each different scenario is a split-second reaction," he said when asked about the November shooting.

Withholding Palestinian bodies

The case has also turned the spotlight on a series of measures adopted by Israel, including the demolition of the homes of some attackers and withholding their bodies.

Some politicians have also encouraged Israeli Jews to carry guns at all times.

Critics say many of the suspects could be tasered and arrested, as was done this month in London when a man stabbed three people in a train station.

Prominent Palestinian politician Hanan Ashrawi said Israel's reaction to attacks is worsening the situation.

Israel's "shoot-to-kill" policy actually "creates more resentment, more anger and is a driving force behind individual cases of revenge," she said.

"When you kill somebody's friend, cousin, sister ... there are people who will go out and seek revenge," she added.

Hadeel's brother was shot in the head and killed two years ago during a protest against the Israeli occupation of the West Bank.

Palestinian President Mahmud Abbas has said that the surge of attacks since October was a reflection of anger at Israel's occupation and the failure of the peace process.

Yoram Schweitzer, a former Israeli military counterterrorism chief, agreed that the lack of progress in peace talks was a factor but said Palestinian assailants cannot escape responsibility.