An investigation by the Israeli human-rights organisation, B'tselem, in cooperation with the Haaretz newspaper, concluded that army accounts of "arrest operations" in the West Banks were not truthful and unreliable.
The joint report contested the veracity of army accounts of the killing on 24 August of five Palestinians at the Tulkarim refugee camp.
The army said the five were terrorists affiliated with the Palestinian resistance movement, Islamic Jihad, who had been involved in attacks against Israeli targets.
However, the B'tselem-Haaretz investigation revealed that three teenage boys killed in the raid had no connection whatsoever with any Palestinian resistance organisation and were completely innocent.
The three were identified as Mahmud Hudeib, Muhammad Othman and Raid Abu Zaina, all 17 years old.
The other two victims, said the report, were "low-ranking operatives who were unarmed and didn't behave like wanted militants".
Israel's military chief Lieutenant-General Dan Halutz on Wednesday ordered an investigation into the West Bank raid that killed five Palestinians after the report was published.
The report quoted witnesses as saying that the five were shot at close range, from 10-15 metres away, while sitting in an enclosed courtyard.
Witnesses reported that soldiers shouted at the five youngsters but then seconds later the soldiers opened fire without giving the men a chance to turn themselves in.
"If you examine the facts objectively, you will see that the army accounts of these operations don't stand the test of reality"
The same witnesses, quoted in the report, said soldiers proceeded to confirm that the boys were dead by shooting them several times from a close range.
The so-called confirmation of killing is a standing instruction in the Israeli army.
Last year, an Israeli soldier operating in Rafah, at the southern tip of the Gaza Strip, shot and killed a nine-year-old Palestinian schoolgirl and then returned to her body, shooting here 20 more times to make sure she was dead.
The soldier, dubbed "Captain R", was acquitted of any wrongdoing and returned to his army unit.
The Israeli army calls such operations in which Palestinian civilians are killed "arrest operations".
However, B'tselem spokeswoman, Sarit Michaeli told Aljazeera.net that in many cases these "arrest operations are in fact assassination operations".
"If you examine the facts objectively, you will see that the army accounts of these operations don't stand the test of reality."
Asked if the army kills these civilians knowingly and deliberately, Michaeli said she could not read what goes inside the soldiers' minds when they kill the civilians.
"When we confront the Israeli Defence Forces (IDF) with our investigations, they stick with their original accounts that the victims were terrorists and that they didn't heed orders to surrender."
Hastily prepared reports
Sarit accused the army of issuing "hastily prepared statements which don't really tell the truth".
B'tselem says 654 children have
been killed since September 2000
"They release hastily prepared accounts within half an hour of the event.
"On the other hand, we present accurate information based on meticulous investigative methods, that is why our reports take two weeks to prepare," Sarit said.
Another B'tselem official, who took part in the investigation of the killings in Tulkarim, described the the so-called arrest operations as "nothing less than extraordinary executions of innocent civilians".
The B'selem official said: "I want to tell you something: The Israeli army kills first and then concocts mendacious accounts of the killings, like claiming that the victims were terrorists, or militants who had been involved in anti-Israeli activities or ordered to stop and refused. It is this kind of organised lies."
The Israeli army normally says its soldiers do not kill innocent Palestinians deliberately.
However, Palestinian officials and human-rights organisations operating in the occupied territories argue that soldiers, acting on Israeli army instructions, often open fire indiscriminately and even nonchalantly for the purpose of killing Palestinians, irrespective of whether they are fighters.
"The Israeli army kills first and then concocts mendacious accounts of the killings, like claiming that the victims were terrorists, or militants"
Rights group B'tselem
According to B'tselem, 3269 Palestinians have been killed by the Israeli army and paramilitary Jewish settlers since September 2000.
About 1700 or just over half of these are believed to have been civilians, including 654 children.
On Tuesday, British newspaper The Guardian published testimonies by Israeli soldiers who said they were instructed to kill innocent Palestinians.
The report quoted an Israeli soldier named Assaf, as saying he shot an innocent Palestinian man because he was ordered "to fire at anything moving".
The paper said the killing was not the first time Assaf had killed a Palestinian civilian under orders.
"Assaf is not alone. In recent months dozens of soldiers have come forward to share their stories of how they were ordered in briefings to shoot-to-kill unarmed people without fear of reprimand," said the report.