Top Israeli officials have vowed to continue attacks on militant group Hamas, as Israeli air strikes pounded the Gaza Strip for a third day.
Israel was fighting a "war to the bitter end" against Hamas, its defence chief said. A top army official said no Hamas buildings would be left standing. About 320 Palestinians have died since Saturday, the UN says. Four Israelis have been killed by rockets from Gaza. There were more air strikes early on Tuesday morning, with 10 reported dead. Palestinian officials said that Hamas-run offices and security installations were targeted, with another 40 people said to be wounded. UN Secretary General Ban Ki-moon has called for an immediate ceasefire. Mr Ban said he was "deeply alarmed" by the escalation of violence in Gaza. While recognising Israel's right to defend itself from militant rocket attacks, he condemned its "excessive use of force". Israel has massed forces along the boundary with Gaza and has declared the area around it a "closed military zone".

Correspondents say the move - in addition to the call-up of thousands of reservists - could be a prelude to ground operations, but could also be intended to build pressure on Hamas. In other developments:

• The Red Cross described the situation in Gaza's hospitals as chaotic, with medical teams "stretched to the limit"
• Gaza's Shifa hospital was evacuated following a rumour that it was about to be targeted - patients and staff later returned
• A small number of wounded Palestinians have begun passing through the Rafah crossing into Egypt for treatment; trucks laden with medical aid have been permitted to cross into Gaza
• European Union foreign ministers are to meet in Paris on Tuesday to discuss the escalating crisis

Dozens of centres of Hamas strength, including security compounds, government offices and tunnels into Egypt, have been hit since Israel started its massive bombing campaign on Saturday morning. See detailed map of attacks Early on Monday, raids damaged both the interior ministry and a science building at the Islamic University in Gaza, from which many top Hamas officials graduated. Places hit by later strikes included the home of a senior Hamas commander and a car carrying gas cylinders, reports said. Five sisters were killed in one attack in the densely-populated Jabaliya area. Police help an Israeli woman in shock following a rocket attack from Gaza on south Israeli town of Sderot (29/12/2008) Israelis in nearby towns have faced an escalated militant rocket threat UN humanitarian chief John Holmes said his latest information was that about 320 Palestinians had been killed and 1,400 injured. "Sixty-two of those killed, we believe... are civilian casualties," he told a news conference. "That simply encompasses those who are women and children. It does not include any civilian casualties who are men - even though we know that there have been some civilian men killed as well." Palestinian hospital sources put the death toll higher, with 345 people killed and 1,650 injured. Israel reported its second fatality, a labourer at a building site in the city of Ashkelon that was hit by a medium-range Grad missile. Three people were seriously wounded in the attack. Late on Monday, Israeli media reported two more deaths from rocket fire in the space of an hour, at Nahal Oz near the border with Gaza and in the southern city of Ashdod. Several people were injured in the attacks. Israel says its aim is to end the rocket attacks by Hamas-linked militants - of which there were more than 40 on Monday, the Associated Press news agency said. Defence Minister Ehud Barak said Israel was not fighting the residents of Gaza, but wanted to deal Hamas a "severe blow". The Israeli operation would be "widened and deepened as needed", he said. The army's deputy chief, meanwhile, said that there would "not be a single Hamas building left standing in Gaza" after the operation. Deputy Prime Minister Haim Ramon went further. "The goal of the operation is to topple Hamas," he said. 'Durable ceasefire' UN chief Ban Ki-moon called on both Israel and Hamas to "halt their acts of violence and take all necessary measures to avoid civilian casualties". UN Secretary General Ban Ki-moon has called for an immediate ceasefire "The suffering caused to civilian populations as a result of the large-scale violence and destruction that have taken place over the past few days has saddened me profoundly," he said. The US - Israel's strongest ally - says the onus is on Hamas to end the violence and commit itself to a truce. But there have been angry protests against the Israeli action in many cities across the Arab world and in several European capitals. In Lebanon, tens of thousands of people took part in a demonstration in the capital, Beirut. The strikes began less than a week after the expiry of a six-month-long ceasefire deal with Hamas, which has controlled Gaza since 2007. Analysts said Saturday was the single deadliest day in Gaza since Israel's occupation of the territory in 1967. Israel withdrew in 2005 but has kept tight control over access in and out of Gaza and its airspace. The exiled leader of Hamas, Khaled Meshaal, has called for a new intifada, or uprising, against Israel. Hamas's advisor on foreign policy, Dr Ahmed Yousef, warned that the Israeli operation could lead to suicide attacks. "The scale of damage, they're destroying all the government buildings and mosques, schools, amenities," he told the BBC's World Tonight programme. "When the people look to these crimes and the scale of damage that's happened here, yes, some of the people will go to get revenge."

GAZA CAMPAIGN DEATHS
320 - Official Gaza toll (source: UN
62 civilians in Gaza (source: UN)
4 civilians in Israel (source: Israel police)