UN Secretary General Kofi Annan set off an international war of words Tuesday evening when he called the Israeli shelling of a UN peacekeeping post in southern Lebanon "an apparently deliberate act."

Four unarmed military observers — one each from China, Austria, Finland and Canada, Kingston-based Maj. Paeta Hess-von Kruedener — are believed killed during hours of bombardment, which included a laser-guided aerial bomb.

• YOUR SPACE: Your letters on the shelling of a UN outpost

Three of the bodies have been recovered. Maj. Hess-von Kruedener is missing and presumed buried in the rubble.

Israel strongly denied that it had targeted the UN personnel, or the patrol post at Khiyam, which sits atop a plateau and has been under direct UN command since 1978. Though on Thursday, two days after the incident, Brig.-Gen. Shuki Shahar, deputy chief of the Israeli military's Northern Command, said soldiers in the field had accidentally called in the co-ordinates of the UN base and that the air strike had been approved by senior officers. "Sometimes mistakes are made and innocent people are hit," he told reporters outside his field tent. "We do the best we can. We didn't recognize it as their base."

Earlier Thursday, a UN spokesperson said Annan accepted Israel's assurances that the attack was not deliberate. The UN, however, is pressuring Israel to make its promised inquiry into the affair a joint one, something Tel Aviv is resisting.

Here at home, Prime Minister Stephen Harper said he did not view the act as deliberate and felt Israel was genuinely sorry for what happened. He also wondered aloud why the UN would keep its unarmed observers in the middle of a war zone.

Around the world, reaction has been sharply divided and many countries have been harshly critical of Israel for shelling the post even after having been repeatedly warned by senior UN officials that peacekeepers were inside. China in particular strongly condemned Israel's actions and accused the U.S. of watering down a Security Council motion dealing with the attack.

What we know so far

According to UN spokespeople and a preliminary report by the agency, the Khiyam post had been under fire for six hours, beginning at 1:20 in the afternoon, while those inside were pleading for help.

The accounts vary slightly. But most say the base and its immediate area were hit 21 times. At least 11 of these were aerial bombardments and four were direct hits, including a large laser-guided bomb loosed from an aircraft straight into the bunker.

There are three ways such a bomb is directed. It could be set by a special-ops team in the field that marks the target with a laser, by a second plane using its laser as a guide, or by the bombing plane itself, marking the site first with a laser and then delivering the ordnance. This was how four Canadians were killed in Afghanistan four years ago during the so-called friendly fire incident.

In any event, shortly after the first series of artillery shells began to rock the post, senior UN commanders in the region got on the phone to their Israeli counterparts and told them to stop the bombardment. At least six calls were made by the immediate commander for the area, Lt.-Col. John Molloy, an Irish officer. Others came from Maj.-Gen. Alain Pellegrini of France, the man in charge of the 2,000-strong United Nations Interim Force in Lebanon (UNIFIL), as well as from senior UN bureaucrats in New York.

By early evening, after the UN lost radio contact with the Khiyam post, it secured assurances from the Israelis to allow a small contingent of Indian peacekeepers to approach the summit. They, too, were shelled briefly on their way up.

Why were the four at Khiyam?

Maj. Paeta Hess-von Kruedener was the only Canadian serving as a UN military observer in Lebanon. He had been an instructor at the Peace Support Training Centre in Kingston, Ont. (Canadian Armed Forces-G. LeClair/CP)

The simple answer is they were doing their job. Maj. Hess-von Kruedener had been based at Khiyam since October. The group was to monitor ceasefire violations between Hezbollah militants and the Israeli army in their area of the so-called buffer zone in southeastern Lebanon.

This is something UNIFIL has been doing since 1978, after Israel invaded its northern neighbour for a second time following a prolonged border skirmish. The UN role was downgraded to observer status in 2000, after Israel pulled its troops out of Lebanon, seemingly for good.

• See Reality Check: Peacekeeping in Lebanon, can it work?

The UN has 1,990 peacekeepers in southern Lebanon, as well as 50 military observers (Maj. Hess-von Kruedener's status) and about 400 civilian assistants. UNIFIL operates at least 90 formal observation posts in southern Lebanon at a cost of almost $100 million US a year. It's total cost since 1972 is something in the neighbourhood of $3.7 billion US.

Why were the four unarmed observers at Khiyam in the midst of a major military escalation? That's a much more subtle question that probably has as much to do with concepts such as duty and esprit de corps as anything else. The fact is, until the attack on Khiyam, UNIFIL was still attempting to do its job during the current crisis. Only after the attack did Australia move its peacekeepers north to the relative safety of Beirut.

Much of this exalted sense of duty can be laid at the feet of the Irish. They've been the largest contingent of peacekeepers in Lebanon, rotating some 30,000 men and women through between 1978 and 2001, and suffering 47 casualties in the process.

What the Irish did, though, according to the histories of the mission, is set the standard for peacekeeping. They risked their lives during onslaughts of shelling, particularly in the late 1990s, to distribute food and medicine. They accompanied farmers to and from their fields often under the mistrustful eyes of both the Israeli army and militant groups; they helped build schools and they opened their bunkers to local residents whenever the bombardments became too much.

"People build houses around the UNIFIL positions," one Irish officer explained a few years ago. "If UNIFIL wasn't here, the population wouldn't be here."

A history of casualties

The deaths at Khiyam weren't the first UN casualties in Lebanon. They weren't even the first since this current round of fighting began: A Nigerian peacekeeper was killed a week ago by an Israeli bomb when he left his post to retrieve some personal items from his home in a suburb of Tyre as it was under attack.

Since it began its mission in southern Lebanon, the UN has lost 262 personnel. It's a dangerous place in which Hezbollah routinely attempts cross-border raids or rocket attacks and Israel responds with artillery or aerial bombardments.

In the past two weeks of heavy fighting, there have been 145 incidents of "close firing" near UN posts and four sites have suffered direct hits, UN spokespeople say. All are believed to be by Israeli forces.

Peacekeepers might have thought they would be immune from such attacks. In 1996, during a similar kind of campaign, an Israeli bomb killed over 100 civilians who were sheltering at a UN post. The international outcry from that incident was huge.

But as Maj. Hess-von Kruedener phlegmatically observed a week ago, in an e-mail to CTV: "We have on a daily basis had numerous occasions where our position has come under direct or indirect fire from both artillery and aerial bombing. The closest artillery has landed within two metres of our position and the closest 1,000 [pound] aerial bomb has landed 100 metres from our patrol base.

"This has not been deliberate targeting," he said, "but has rather been due to tactical necessity."

That last line has been read to imply that Hezbollah fighters also use the UN posts as cover from which to launch their rocket attacks and Israel is trying to hunt them down.

On the day in question, however, the UN stressed there were no Hezbollah spotted within at least a kilometre of the Khiyam post. Though that is not a great distance to cover in a pick-up truck full of small rockets.

Why would Israel target the Khiyam post?

The constancy of the Israeli bombardment, over six hours in duration and involving both artillery and the air force, says this incident was not simply a one-off mistake by some kind of cowboy pilot.

The most common explanation for what occurred is that Israeli officers felt there were Hezbollah fighters trying to use it as a shield and that decisions were being made at a very local level.

The Khiyam post is not only one of the oldest (and best marked) UN posts in southern Lebanon, it is also one of the more strategic. It is on a plateau that overlooks an expansive valley to the south, a valley that has often been an important invasion route in the past.

The post is also said to enjoy a commanding view of the Israeli army's forward positions on the Golan Heights to the east. So from an Israeli point of view it would be a key enemy launching site if it could be controlled, even for a short time.

A more Machiavellian interpretation is that Israel was trying to send a message to the international community, perhaps not realizing that the post was still occupied, to deter it from sending in a more robust peacekeeping force that might prevent Israel from dealing with Hezbollah as it saw fit.

The only problem with that theory is that Israel itself has called for an international force to police southern Lebanon and help it control Hezbollah. That appeal is likely to fall on many more deaf ears now.

[an error occurred while processing this directive]