By Alistair Lyon, Special Correspondent/Reuters
BEIRUTâ€”Israelâ€™s killing of four U.N. observers piled pressure on an international conference in Rome on Wednesday to end a 15-day-old Middle East conflict, as Hezbollah vowed not to accept any â€œhumiliatingâ€ truce terms.
United Nations Secretary General Kofi Annan demanded Israel investigate the â€œapparently deliberate targetingâ€ of a U.N. post in southern Lebanon where an Israeli air strike killed the four U.N. military observers on Tuesday.
Israel, waging a military offensive in Lebanon against Hezbollah guerrillas, announced it would hold a probe and expressed regret at the deaths but said it was shocked Annan had suggested the observers may have been deliberately targeted.
A Chinese national was among the four observers killed, Chinaâ€™s official Xinhua news agency reported. It said the other three were from Finland, Austria and Canada.
U.N. officials said the air strike had caused the building housing the observers to collapse and that rescue teams had been sent to retrieve the bodies from the rubble.
â€œ(This) attack on a long established and clearly marked U.N. post at Khiam occurred despite personal assurances given to me by (Israeli) Prime Minister Ehud Olmert that U.N. positions would be spared Israeli fire,â€ Annan said in a statement.
With international concern already high over civilian casualties, Lebanon and its Arab allies will plead at the Rome talksâ€”due to start at 0800 GMTâ€”for an immediate truce but Washington says a lasting solution needs to be agreed first.
Israel, with apparent U.S. approval, has said it would press on with its offensive. It also said it planned to set up a â€œsecurity stripâ€ in Lebanon until international forces deploy.
â€œWe cannot accept any condition humiliating to our country, our people or our resistance,â€ said Hezbollah leader Sayyed Hassan Nasrallah, whose group triggered the war by capturing two Israeli soldiers in a July 12 cross-border raid.
The war, in which 418 people in Lebanon and 42 Israelis have been killed, was entering a new phase, Nasrallah said in a televised address.
â€œIn the new period, our bombardment will not be limited to Haifa,â€ he said, suggesting his guerrillas would hit towns deeper inside Israel. Hezbollah has hit Haifa, Israelâ€™s third largest city 35 km (20 miles) south of Lebanon, for the first time with rockets.
Israel has also been waging a military campaign in Gaza since June 28 to recover a soldier seized by Palestinian militants. Eight Palestinians were killed on Wednesday, seven by what witnesses described as a tank shell attack and what the Isareli army said was an air strike aimed at militants.
Arab leaders and Annan want the Rome conference to call a quick halt to the conflict but U.S. Secretary of State Condoleezza Rice, who has visited Beirut and Jerusalem, says she prefers to get conditions right for â€œa durable solution.â€
Israel and Syria, Hezbollahâ€™s main ally along with Iran, have not been invited to the Rome conference.
Hezbollah wants a truce to be followed by talks on swapping the two Israelis for Arab and Lebanese prisoners in Israel. The United States demands Hezbollah free the soldiers unconditionally and pull back from the border before disarming.
Jordanâ€™s Foreign Minister Abdelelah al-Khatib spoke of a â€œclear Arab stance in Rome demanding an immediate ceasefireâ€ and Italian Prime Minister Romano Prodi said Italyâ€™s priority for the talks was a ceasefire, followed by humanitarian assistance.
Saudi Arabia, a key U.S. ally, has blamed Hezbollah for starting the fighting, but in outspoken new comments King Abdullah said Israel risked sparking a wider regional war.
Israel, the United States and European countries agree on the need to see Hezbollah disarmed, but some of the Europeans think this should not be a precondition for any peace deal.
The Rome meeting will also seek agreement on what kind of international force could be sent into southern Lebanonâ€”a mission fraught with danger unless Hezbollah consents.
U.N. humanitarian agencies said they were still largely blocked from getting relief supplies into Lebanon and from getting wounded and very sick people to hospitals.
Lebanon says Israelâ€™s bombardment has displaced a fifth of its population. Most of its dead are civilians.
Israel launched air strikes in Gaza on Wednesday, killing a Hamas militant and wounding at least 8 other Palestinians, witnesses said. Israeli tanks backed by helicopter gunships pushed nearly 1 km (0.6 miles) into the northern Gaza Strip.
A total of 131 Palestinians have been killed Israelâ€™s month-long offensive in Gaza.