Anger and anguish as Gaza toll mounts

Israel says no immediate end to fight in Gaza... 02:27

GAZA CITY -- Israeli Prime Minister Netanyahu said Thursday morning that the destruction of Hamas tunnels from the Gaza Strip will go on, "with or without a cease-fire." Meanwhile, Israel is calling up 16,000 more reservists to, as officials put it, let soldiers now in Gaza return to see their families and get some sleep.

Israel clearly has the military high ground in the ongoing fight against the Palestinian militants, reports CBS News' Barry Petersen, but there has been broad condemnation for the Israelis' alleged pre-dawn attack Wednesday morning on a U.N. school in the densely populated Palestinian territory.

Israel barrages Gaza overnight, second U.N. s... 02:29

According to U.N. officials, three Israeli artillery rounds slammed into the facility, which was crowded with more than 3,000 refugees seeking shelter.

The Israelis had encouraged people to use the school as a safe haven because there is fighting all around the area. Israel claimed it was taking fire from near the school, but has not confirmed its artillery caused the damage and civilian deaths.

U.N. Secretary-General Ban Ki-moon called the attack "outrageous."

The Obama administration said it was "extremely concerned," but urged a "full investigation" and wasn't ready to lay the blame on the Israelis.

Hamas, the Islamic militant group that won an election to govern Gaza and has since joined the other major Palestinian faction in the West Bank to form a unity government, called it simply, a massacre.

Even for Chris Gunness, a U.N. spokesmen who has seen the worst of the decades-old Middle East conflict at close range, the school attack was just too much to bear. He broke down in sobs as he tried to finish an interview with Al Jazeera on Thursday.

And after the school attack, there was another killing field; a market where people flocked Wednesday afternoon, thinking they were safe during a four-hour cease-fire Israel had declared.

Relatives of Palestinian girl Layan al-Silk, whom medics said was killed with other family members by Israeli shelling at a market in Gaza City's Shijaiyah district, mourn during her funeral
Relatives of Palestinian girl Layan al-Silk, whom medics said was killed with other family members by Israeli shelling at a market in Gaza City's Shijaiyah district, mourn during her funeral, July 31, 2014. REUTERS

They were wrong, and many paid with their lives. Israel said the cease-fire was broken by Hamas, firing rockets into Israel. On Thursday, a Hamas rocket fell in a park where kids play in the southern Israel town of Sderot. No one was injured.

According to the Israeli government, 2,830 rockets have been fired at the country since the current fighting began. Most are intercepted before impact. In all, 56 soldiers and three civilians have been killed.

Netanyahu warns Israel is prepared for “pro... 01:52

In Gaza, officials said more than 1,357 people had been killed by Wednesday evening, most of them civilians and 315 of them children.

Speaking Thursday, Netanyahu made it clear there was no prospect for a real let-up in the offensive until Israel had accomplished its objectives.

He said the military had "neutralized dozens of terrorist tunnels and we are determined to complete this mission, with or without a cease-fire, and therefore I will not agree to any proposal that does not allow the IDF to complete this work which is important for the security of Israel's citizens."

"We have struck hard at thousands of terrorist targets: Command centers, rocket arsenals, production facilities, launch areas and hundreds of terrorists have been killed," said the Israeli leader, whose popularity among constituents has soared amid the war.

He went on to warn that the Israeli military's "achievements" were "only the first stage in the demilitarization of the Gaza Strip."

Three days ago, Petersen reported on a rare glimmer of hope for one bereaved family in Gaza. Amid the carnage, a baby named Shaymaa was delivered Monday by emergency Cesarean section after her mother was killed in the rampant shelling.

CBS News learned on Thursday that Shaymaa had not survived.

"I hoped she would live," her grandmother Mirvat Qanan told Petersen. "She was my connection to my daughter."

On Thursday, baby Shaymaa was just another addition to the fresh graves in the Gaza Strip, and there was no sign cemetery workers might soon be able to lay down their shovels.