"I assume it will continue for several more weeks, and in a number of weeks we will be able to [declare] a victory," Major General Udi Adam, the head of Israel's northern command, said at a news conference.

Earlier, the United Nations general secretary, Kofi Annan, accused the Israeli military of carrying out a sustained bombing of the UN base on the Lebanon-Israel border that culminated in the killing of four unarmed monitors.

Mr Annan said he had suggested to the Israeli prime minister, Ehud Olmert, that they carry out a joint investigation into the events that led to the shelling of the "well-established and well marked" Unifil (UN interim force in Lebanon) post in the town of Khiyam.

"I spoke to Mr Olmert and he definitely believes it was a mistake and has expressed his deep sorrow, " Mr Annan told a press conference in Rome. "But the shelling started in the morning and went on until after 7pm. You cannot imagine the anguish of the unarmed men and women peacekeepers who were there."

The four monitors came from Austria, Canada, China and Finland. Tonight, European Union and Chinese officials condemned the attack as "unacceptable" and the Irish government filed an official complaint to Israel after its senior UN peacekeeper made half a dozen warning calls over the bombings.

Jane Lute, the assistant secretary general for peacekeeping, told the UN security council that the base came under close Israeli fire 21 times - including 12 hits within 100 metres and four direct hits - from 1.20pm until contact was lost with the four peacekeepers inside at 7.17pm.

Ms Lute said the peacekeeping force had protested to the Israeli army after each firing incident. The UN's deputy secretary general, Mark Malloch Brown, and Ms Lute herself also made several calls to Israel's mission to the UN "reiterating these protests and calling for an abatement of the shelling", she said.

After contact with the base was lost, Unifil then won safe passage for two armoured personnel carriers to evacuate the position, she said. They arrived at 9.30pm "and found the shelter collapsed and major damage to the rest of the position". Despite negotiating safe passage, the APCs also came under Israeli attack, Ms Lute said.

The 2,000-strong Unifil force, which sits on the Israel-Lebanon border, has suffered dozens of attacks and direct hits in the two-week conflict.

The deaths of the monitors cast a shadow over today's meeting in Rome, where foreign ministers gathered to discuss the Israeli-Lebanese crisis. The US secretary of state, Condoleezza Rice, and the British foreign secretary, Margaret Beckett, were among ministers attending the talks in Rome, which ended with no clear indication of when a ceasefire would be achieved.

Tonight, the Italian prime minister, Romano Prodi, said he would be willing to contribute his country's troops to any UN multinational peacekeeping force in southern Lebanon.

Meanwhile, the Israeli military said eight soldiers had been killed and another 22 injured during intense fighting in the southern Lebanese town of Bint Jbeil.

Elsewhere, Israeli forces killed 19 Palestinians in fighting across the Gaza Strip, including at least nine militants, three children and a disabled man, medics and witnesses said.

Israel has stepped up air strikes and launched raids into Gaza to stop rocket attacks and recover a soldier captured by militants on June 25. The army has killed 140 Palestinians since it began its assault.

Elsewhere, the Israeli air force renewed its bombing of Tyre this evening, flattening an apartment block in one attack. The strike appeared to have targeted the seven-storey building housing the headquarters of Sheik Nabil Kaouk, Hizbullah's south Lebanon commander. The building was empty but 12 people nearby were injured.

Israeli forces encircled Bint Jbeil yesterday, with one commander describing it as the "capital of Hizbullah". The army said then that it had killed up to 30 militants as it aimed to dismantle Hizbullah command posts there and destroy rocket launchers.

Mr Olmert was today facing mounting pressure to endorse calls for an immediate ceasefire amid claims that his position and that of the Bush administration were putting civilian lives at risk. In Britain, aid agencies, religious groups and the public sector union, Unison, wrote an open letter to Tony Blair condemning his refusal to back the UN's demands for a ceasefire.

The letter - signed by 14 organisations including Amnesty International, Christian Aid and the Muslim Council of Britain - warned that the UK government was diluting calls for peace. "By failing to back the UN and call for an immediate ceasefire, the UK government has reduced the impact of international calls for an immediate halt to the violence," the letter said.

A spokesman for Mr Blair said the prime minister was engaged "almost on an hourly basis" in trying to secure support for a stabilisation force and was ready to take "heat" from critics. The government hoped to secure "broad agreement in principle" in Rome to the idea of a stabilisation force, the spokesman told reporters.

Israeli warplanes bombed 100 targets in southern Lebanon yesterday and one family of seven civilians was killed. More than 400 Lebanese have been killed in total. Hizbullah yesterday fired some 70 rockets into northern Israel, killing a 15-year-old girl. More than 40 Israelis have died in the violence, including 18 who have been killed by rockets.