The al-Aqsa Hospital in central Gaza was hit by Israeli tank shells on Monday, killing four people and injuring 60 others. It is the third time a hospital has been hit during the two week Israeli offensive. Assaults on hospital are considered war crimes under international humanitarian laws, if they are deliberate. Israeli forces maintain Hamas stored anti-tank missiles near the hospital.

Over the weekend, the people of Gaza suffered the highest death toll since Israeli's offensive began two weeks ago, and started ground invasions, with at least 87 people reported killed on Sunday, with 67 in one area. In total over 500 Palestinians have been killed with over 3,300 wounded, and 27 Israelis killed since Israeli's campaign began.

"I want to note that Secretary Kerry has departed for the Middle East. As I've said many times, Israel has a right to defend itself against rocket and tunnel attacks from Hamas," President Obama said about Gaza on Monday at the White House. "[I]'ve also said, however, that we have serious concerns about the rising number of Palestinian civilian deaths and the loss of Israeli lives. And that is why it now has to be our focus and the focus of the international community to bring about a cease-fire that ends the fighting and that can stop the deaths of innocent civilians, both in Gaza and in Israel."

Secretary of State John Kerry flew to Cairo on Monday to join a diplomatic effort towards a cease fire and truce, joined by U.N. secretary-general, Ban Ki-Moon who spoke to reporters.

"While I was en route to Doha, dozens more civilians, including children, have been killed in Israeli military strikes in the Shejaiyah neighborhood in Gaza," Ban said. "I condemn this atrocious action. Israel must exercise maximum restraint and do far more to protect civilians."

Ban is currently reviewing a request by Abbas which would place Palestine under an international protection system administered by the U.N.

Cairo's cease-fire plan is backed by the U.S. and Israel. But Hamas has rejected the Egyptian plan and is relying on governments in Qatar and Turkey for an alternative proposal, according to The Associated Press.  Qatar and Turkey have ties to the Muslim Brotherhood, which is also linked to Hamas but banned in Egypt.

Ismail Haniyeh, the top Hamas leader in Gaza, said Monday his group would stick to the demand that before halting fire, it wants guarantees that Israel and Egypt will significantly ease a seven-year border blockade of Gaza as first reported by The Associated Press.

Israeli forces have conducted four ground incursions into Gaza, 90 airstrikes, firing 91 misslies, as well as more than 500 shells. Hamas has fired 2,000 rockets at Israel.

The U.N. relief agency in Gaza estimates that 100,000 Palestinians have fled their homes since the fighting began, and 84,000 are seeking shelter in 61 schools and other shelters the United Nations has set up.

Veterans groups are speaking out. Veterans for Peace sent a letter to the Israeli Ambassador to the United States Ron Dermer on Monday which said, "As veterans who have witness the horror of war, we are deeply outraged by the state of Israel's slaughter of many innocent civilians in Gaza. The military assault against children, women and men, by air, by sea and now by land, is a clear violation of international laws of war and human rights. More than 300 Palestinians have been murdered, almost all of them civilians, nearly a quarter of them children. Thousands are wounded, including nearly a 1,000 children.

"Mr. Ambassador, please remind the government of Israel of the billions of dollars in aid that is provided to Israel by the United States. Veterans For Peace will push for an end to all military aid to Israel until such time as the Israeli occupation gives way to real peace negotiations based on the human rights of all people concerned."

Veterans for Peace is a global organization of military veterans and allies with 140 chapters worldwide.