Women and children seeking shelter in the UN-protected facility among the dead as conflict escalates.
Israeli tanks and troops blazed into towns across the Gaza Strip on Tuesday in the bloodiest day yet of the ongoing conflict.
Among the casualties were at least 48 people seeking shelter at three UN-run schools.
While troops battled Islamist militants along the back alleys of Gaza's main city in the heaviest fighting of the 11-day-old offensive to halt cross-border rocket attacks, Hamas still made its deepest rocket strike yet into Israel.
As the Palestinian death toll hit 660, Arab nations pressed for a UN Security Council resolution condemning the onslaught, but Israel rejected ceasefire calls by French President Nicolas Sarkozy and other leaders.
The United Nations demanded an investigation after tank and air assaults hit three schools run by the UN Palestinian relief agency, UNRWA. At least 43 people who had taken shelter at the Jabaliya refugee camp school in northern Gaza were killed, according to emergency servics.
The United Nations confirmed at least 30 dead and 55 wounded after the tank shells hit. The Israeli military said a preliminary inquiry indicated that a number of mortar rounds may have been fired from the Jabaliya school.
Earlier two people were killed when an artillery shell slammed into a school in the southern city of Khan Yunis. Three people also died in an air strike on another school in the Shati refugee camp in Gaza City, medics said.
UN Humanitarian Coordinator for the Palestinian territories Maxwell Gaylard said Israel had the GPS coordinates of all UN buildings in Gaza -- including schools. "Neither homes nor UN shelters are safe" for civilians , he said in a statement which reaffirmed UN ceasefire calls.
He called for an investigation "and if international humanitarian law has been contravened, those responsible must be held accountable."
Heavy fighting raged in Gaza City and around nearby Deir al-Balah and Bureij. One air raid killed 12 people, including seven children, from the same family in Gaza City. Tanks supported by helicopter gunships rolled into Khan Yunis before dawn, to be met by return fire from Hamas and its allies, witnesses said.
Four Israeli soldiers were killed in two friendly fire incidents during the overnight surge in fighting, the army said. Five have now died since Saturday. The military said another soldier was killed in a clash near the territory's main city. It also said that paratroopers shot at the belt of a suicide bomber running towards them to detonate his bomb. About 35 Hamas rockets were fired over the border, one landing 45 kilometres (28 miles) inside Israel -- the deepest yet -- slightly wounding a baby, it said.
Three civilians and one soldier have been killed by rocket fire inside Israel since the offensive began.
Israel launched Operation Cast Lead on Hamas on December 27 with a massive air bombardment of Gaza, and sent in thousands of ground troops a week later.
Since then, 660 Palestinians have been killed, including about 200 children , with more than 2,950 wounded, Gaza medics say.
(hope you can print this lettter without amendment please) The total disregard for the United Nations, humanity, women, children, mosques, schools and the stubbornness with which a state is continuing its terror is very appalling, disgusting and very sad. After a year long siege, would you expect the Gaza residents to throw flowers and not rockets on Israel? The disproportionate use of force by Israel will only produce more rebels and the Palestinian survival itself out of this mess will be considered a victory unless Israel with its patrons US & UK consider nuking them and it won't come as a surprise at least to me. Jewish terrorism at its peak and they are not like normal people. Subsequently, the UN will be paralysed with the Vetos and Arab states will remember the martyrs on every anniversary and then busy themselves with important jobs or becoming super-rich.
The fact that Israel is targeting schools and mosques shows their aim is annihilation of the Gaza strip and all its occupants - not just to stop rocket fire from Hamas. The UN is a toothless tiger considering the power of the UN lies in the Superpower's Veto - they can overturn a majority vote. As the Superpowers have no interest in stopping the carnage as they support and supply Israel with their weapons the rest of the world can sit by idly saying " tutt tutt" while the genocide continues. The real targets here are the women and children of Palestine - the future of their race - if there are no women and no children who will carry on the names????????????? SHAME SHAME SHAME for all the Arabic governments who stand by silently and watch the massacre - guilty by apathy to help fellow Muslims in their time of need. There are more ways than violent ones to bring the super powers to their knees. It will just take a combined effort to stop this carnage. Act now before there is no-one to act for in Gaza - just a pile of graves
It is absolutely heart wrenching to view the numerous photos of bloodied dead babies and children everyday on the newspapers and TV, yet there are no leaders standing up to discriminate against such ordeals. Some have made statements and have "called for an immediate cease-fire" such a cliched statement which is not apt for the terrorism induced by Israel. I cannot believe many of the Arab leaders are sitting back and doing nothing, oh yes they are sending money as compensation but don't want anything to do with what is going on as this will ruin their relations with the West. This just sickens me. While countries are trying to recover their financial loses, they are really turning a blind eye towards a blood filled crisis and what is alarming is that people are out there on the streets voicing their opinion and, NOT ONE, leader is listening to the concerns and doing anything about it! UN can call meetings upon meetings but Israel will still not listen or comply to any resolutions. On the other hand we must resolve to listening to our Western counterparts as they have more wisdom in such matters. .simply appalling.
I totally agree with previous commenter, as a dual national of US and UK. I am absolutely disgusted that neither of these countries is doing anything to stop Israel in this atrocity. Is there no one in this world that has any guts to do the right thing?
Where is the illicit father and self proclaimed leader of the world United States of America, if it is really concerned with the issue of the world, why is it turning a blind eye to the war in Palestine. Just to have political mileage and support of the few top Israelis, it is justifying the killings of the innocent human beings in Gaza. Where are the UN and NATO peace keeping force? Why are they wasting time in Afghanistan and Iraq where they are not needed.