JERUSALEM (AFP) — The Israeli army conceded Monday for the first time that one of its soldiers had likely shot Palestinian-American reporter Shireen Abu Akleh after having mistaken her for a militant.

"There is a high possibility that Ms. Abu Akleh was accidentally hit by IDF (Israel Defense Forces) gunfire that was fired toward suspects identified as armed Palestinian gunmen," the army's final investigation report into her 11 May death said.

The acknowledgement comes after months in which the army had insisted it was impossible to determine the source of the deadly shot that killed the celebrated Al Jazeera journalist in the occupied West Bank, saying it could have been militant fire.

"Our conclusion is that it's not possible to determine unequivocally which gunfire killed her, but there's a higher probability that she was hit by an errant shot of an IDF soldier who did not identify her as a journalist," a senior Israeli military officer said.

Abu Akleh was wearing a bulletproof vest marked "Press" and a helmet when she was shot in the head during an Israeli army operation.

The Abu Akleh family said that Israel had "refused to take responsibility for the murder" of the journalist, in a press release issued in the wake of the army's report.

"We remain deeply hurt, frustrated and disappointed," the family said, calling for a "credible" United States investigation.

The Palestinian Authority accused Israel of intentionally killing the reporter in the Jenin refugee camp, in the northern West Bank, whereas Israel has insisted that even if a soldier fired the fatal shot, it was not deliberate.

Al-Jazeera said it denounced the findings of the Israeli investigation and demanded a probe by an "independent international body."

"Al Jazeera condemns the Israeli occupation forces' reluctance to explicitly admit their crime and attempts to evade the prosecution of the perpetrators," it said in a statement.