An  IAF strike in on the building of a UN observer force killed four the town of Khiyam near the eastern end of the border with Israel.

The four UN monitors died when Israeli warplanes attacked their post. They came from China, Canada, Finland and Austria. Unifil (UN interim force in Lebanon), a 2,000-strong force, on the Israel-Lebanon border. has suffered dozens of attacks and direct hits in two weeks of conflict between Hezbollah and Israel.

An Israeli tank shell had hit a UNIFIL position in southern Lebanon on Monday, wounding four Ghanaian soldiers. Shrapnel from tank shells fired from the Israeli side seriously wounded an Indian soldier last week and Hezbollah fire wounded an Italian observer on the border on Sunday.

A detailed timeline of the bombing has been provided by UN sources and reported by CNN. According to the timeline, the first bomb exploded around 200 yards from the post at 1.20pm yesterday.Unifil observers then telephoned their designated contact with the Israeli military, who assured them the attacks would stop.

Over the next several hours, nine more bombs fell close to the post, each one followed by a call to the Israeli military, the UN officer said.The main Unifil base in the town of Naqoura lost contact with the post at 7.40pm, seemingly the time when the post received a direct hit.

A report was made by Milos Strugar, a United Nations Interim Force  spokesman, shortly after the bomb hit: "One aerial bomb directly impacted the building and shelter in the base of the United Nations Observer Group in in the area of Khiam," he said. "There are casualties among the observers. A UNIFIL dispatched rescue team which is on the spot is still unable to clear the rubble," he said. He also reported that  Israeli firing continued during the rescue operation

"There were 14 other incidents of firing close to this position in the afternoon from the Israeli," he added. Israel has voiced suspicion of the force in the past.

In Rome, Kofi Annan, the UN secretary-general, said he was shocked at ‘s "apparently deliberate targeting" of a UN post in Lebanon.He also asked to investigate the incident.

Israeli authorities expressed regrets, denying that the attack was deliberate.

Condemnation of the attack came from many nations. Malaysian Foreign Minister Syed Hamid Albar speaking on  Wednesday, after a meeting of the Association of Southeast Asian  Nations had condemned Israeli aggression, said: "I think it is very  easy to express deep regret after the event."

France, whose officers command the 28-year-old UN Interim Forces  in Lebanon, also protested, and China, one of whose nationals  was among the dead, called in the Israeli ambassador in Beijing to demand a formal apology. Finnish President Tarja Halonen  also demanded an investigation: "Nothing can justify ‘s attack  on a UN observer base." 

In 1996, during ‘s Grapes of Wrath campaign in , an Israeli jet bombed a UNIFIL compound in the southern village of Qana, killing 106 civilians sheltering inside.

UNIFIL was created in 1978 after Israel’s first major invasion of southern Lebanon and has been there ever since. The United Nations has called for a bigger, better armed, more robust international force in the area.