Israeli forces - and not Palestinian militants - shot dead a high-profile Al Jazeera journalist, the UN's human rights office has concluded.

A spokeswoman said the findings were the result of "independent monitoring" of the incident on 11 May.

The killing of Shireen Abu Aqla, who was reporting on an Israeli operation in the occupied West Bank, caused widespread outrage.

Palestinians have blamed Israel. Israel says blame cannot yet be determined.

The 51-year-old Palestinian-American journalist was one of the region's most experienced and admired correspondents.

Abu Aqla, who was wearing a protective vest with the word "Press" on it as well as a helmet, was shot in a road near where a gun-battle had taken place between Israeli forces and Palestinian militants.

The Israeli military said its forces had gone into Jenin to apprehend "terrorist suspects" following a wave of deadly attacks against Israelis by Palestinians, two of whom came from the Jenin district.

Eyewitnesses say the fatal shot was fired by Israeli forces, though Israel disputes this. It says it has not yet been possible to establish the source of the gunfire because the Palestinians rejected its request to examine the bullet that killed Abu Aqla or to hold a joint investigation.

Speaking to reporters in Geneva on Friday, Office of the High Commissioner for Human Rights (OHCHR) spokeswoman Ravina Shamdasani said the department had found that "the shots that killed Abu Aqla and injured her colleague Ali Sammoudi came from Israeli security forces and not from indiscriminate firing by armed Palestinians, as initially claimed by Israeli authorities".

"It is deeply disturbing that Israeli authorities have not conducted a criminal investigation," she added.

Ms Shamdasani said the information had come from the Israeli military and the Palestinian attorney general.

She said that on the morning of the incident, four journalists turned into a street whereupon "several single, seemingly well-aimed bullets were fired towards them from the direction of the Israeli security forces.

"One single bullet injured Ali Sammoudi in the shoulder; another single bullet hit Abu Aqla in the head and killed her instantly."

The Israel Defense Forces (IDF) responded to the OHCHR's allegation, saying it could not be proven which side shot Abu Aqla.

"An IDF investigation states that the journalist was in no way shot intentionally, and it is not possible to determine whether she was killed by Palestinian gunmen shooting indiscriminately in her area or inadvertently by an IDF soldier."

Israel has said it has identified a soldier's weapon which might have fired the shot, but that it cannot be certain without analysing the bullet. The Palestinians say they will not hand it over because they do not trust the Israelis.

Ms Shamdasani said the OHCHR had "found no information suggesting that there was activity by armed Palestinians in the immediate vicinity of the journalists".

Last month, a Palestinian investigation concluded that Abu Aqla was intentionally shot dead by an Israeli soldier.

The Israeli defence minister rejected the report, calling it "a blatant lie".