Israeli missile strike hits near U.N. school in northern Gaza, killing several people

The Israeli military stepped up its offensive in Gaza Tuesday, surrounding densely populated Gaza City with its ground forces after at least 50 air strikes pounded the region overnight.

The United Nations said one Israeli air attack struck an elementary school in Gaza City where hundreds of Palestinians had taken shelter, killing three men.

The United Nations Relief and Works Agency said Asma Elementary school was clearly marked as a U.N. installation. It said over 400 people had been given shelter at the school when it was hit Monday night.

"Well before the current fighting, UNRWA had given to the Israeli authorities the GPS (global positioning system) co-ordinates of all its installations in Gaza, including Asma Elementary School," the agency said in a news release.

"UNRWA is strongly protesting these killings to the Israeli authorities and is calling for an immediate and impartial investigation," it added.

Other air strikes hit the homes of people linked to Hamas, including the Wadi family in Jabalya, Hamas security sources said. Eight people were killed in that strike. An overnight air strike hit the Jabalya home of Imad Siam, one of the leaders of Hamas' military wing. Another attack hit the home of a Hamas-affiliated family in Gaza City, killing at least three, according to an eyewitnesses.

Israel claimed Tuesday to have killed 130 Hamas fighters since beginning a ground offensive at the weekend.

As its forces continued to encircle Gaza City -- which has a population of about half a million people -- European diplomats swarmed into the region trying to pull together the elements for a cease-fire. But neither Israel or Hamas has showed any real interest in international calls for a truce.

Israeli Prime Minister Ehud Olmert told French President Nicholas Sarkozy Monday that Israel wanted a "full solution" to the conflict, not just a cease-fire that allowed Hamas to fortify itself, Mark Regev, Olmert's spokesman said.

"Before the last cease-fire with Hamas began, Hamas had missiles with a range of 20 kilometers," Regev said Tuesday. "By the end of the cease-fire, the range of the missiles grew to 40 kilometers. Israel does not want the next cease-fire to allow them to get missiles with a range of 60 kilometers."

A Hamas rocket penetrated farther than ever before into Israel on Tuesday, landing in the town of Gadera, about 36 kilometers (23 miles) north of the Gaza border, the Israeli military said. On Monday, a rocket hit a kindergarten in Ashdod, about 26 kilometers (16 miles) north of Gaza.

Hamas had fired 30 rockets at Israel by Tuesday afternoon, the Israeli military said. Hamas spokesman Abu Obeida warned Israel that the militants would continue rocket attacks "for many months" and vowed to strike deeper into Israeli territory.

Three Israeli soldiers were killed in northern Gaza late Monday in a "friendly fire" incident involving an explosion from a tank shell that hit a building the troops were in, bringing the Israeli troop deaths from the Gaza ground operation to five, the military said. Two dozen troops were wounded in the explosion -- one critical, three severely.

With no end in sight to the conflict, the humanitarian situation has deteriorated. Hundreds of wounded people swarmed into Gaza's largest hospital and scores of Gazans headed for the morgues -- where two bodies are crammed into each drawer.

"Everybody here is terrorized by the situation," John Ging, the director of the U.N. Relief and Works Agency in Gaza told CNN, from Gaza City. "There's no place that you can be safe if you're a civilian here. It's not safe in your home.

The Israeli military said another 80 trucks with humanitarian aid would be allowed to pass into Gaza on Tuesday at the Kerem Shalom crossing

According to Palestinian medical sources, at least 23 people were killed in Gaza on Tuesday, bringing the Palestinian death toll to 555 since Israel launched its operation on December 27. Most of the deaths are militants, but include at least 100 civilians, the sources said. Another 2,750 Palestinians have been injured, most of them civilians, the sources said.

The Israeli ground assault was launched Saturday night. Israel says it is the second phase of an operation to stop militants from firing rockets and mortars into southern Israel.

The incursion followed eight days of air strikes on the territory to stop the rocket attacks, which have killed four Israelis since the military operation began.