OTTAWA — The decision had been made to evacuate a Canadian military officer and three other United Nations observers shortly before they were killed by an Israeli air strike in South Lebanon nearly two years ago, a Canadian Forces board of inquiry has found.

The deaths of Canadian Maj. Paeta Hess-Von Kruedener and three other UN observers were "tragic and preventable'' and were the result of errors by the Israeli Defence Force, the board said.

The UN observers died when their compound was hit by a 500-kilogram bomb delivered by an Israeli aircraft. The compound was also hit by four 155-mm artillery shells fired by the Israelis during clashes with Hezbollah, the report says.

"As the shelling and bombing in the vicinity of Patrol Base Khiam increased in frequency and accuracy, the decision was made to evacuate,'' said the report. "But the fatal bomb was dropped before the four observers could be withdrawn.''

The heavily censored report says the compound's main building was nearly destroyed by the strikes.

The report's 13 recommendations include calls for better communication and situational analysis, but it found no fault with UN command in the area of operations.

The incident occurred two weeks after two Israeli soldiers were captured and the IDF launched incursions against Hezbollah refuges across the border in Lebanon.

Both the UN and Canadian chains of command were aware of the risks of the peacekeeping operation, says the report, but the Canadians deferred to the UN on all tactical decisions.

"The board finds that Major Hess-Von Kruedener died on 25 July 2006 between 1925 hrs and 1930 hrs at Patrol Base Khiam in South Lebanon as a result of an explosion caused by a 500 kg GPS-guided Joint Direct Attack Munition (JDAM) bomb delivered by an Israeli air force aircraft.''

It could not assign blame beyond the Israeli military "as an institution'' because neither the United Nations nor the Israeli Defence Force fully co-operated with the investigation.

The Canadian inquiry says the Israelis provided a "non-paper'' -- apparently oral -- summary of their findings in the incident but it says it was of limited use.

"This was a tragic accident that demonstrates the very real dangers inherent in the work that members of the Canadian Forces are asked to do on a daily basis,'' the chief of defence staff, Gen. Rick Hillier, said in a prepared statement.

"The board's findings and recommendations will improve the safety of the young men and women who proudly wear our uniform. Maj. Hess-Von Kruedener did not die in vain and we shall never forget his ultimate contribution in the pursuit of peace.''

Hess-Von Kruedener and the other observers were working as part of Operation Jade on behalf of the UN Truce Supervision Organization.

The Canadian board is an administrative inquiry normally convened to examine and report on "complex or significant events.''

Its aim is to determine what happened, how and why it happened, and to propose measures that might prevent recurrences. It is not a criminal investigation.