UNITED NATIONS (AP) — Secretary-General Ban Ki-moon will leave Saturday for the Middle East to help mediate the conflict in Gaza between Israel and Hamas, a UN official said Friday.

Under-Secretary-General for Political Affairs Jeffrey Feltman also said at a UN Security Council emergency meeting on the conflict in Gaza that a ceasefire is “indispensable” for urgently needed humanitarian efforts to succeed. He said the UN refugee agency was already stretched to its limit.

The Palestinian UN ambassador threatened to go to UN and international courts, which would likely include the International Criminal Court, if the Security Council doesn’t act to protect Palestinian civilians from Israeli attack and end the conflict in Gaza.

Riyad Mansour said that Israel’s “savage” aggression into Gaza “cannot be justified by any means.”

“It is not self-defense,” he said. “It is a vengeful military aggression intentionally planned and perpetrated by the occupying power on the civilian population under its occupation.”

Mansour said the Israeli campaign is designed to destroy “Palestinian unity and collapse of the national consensus government.”

Israeli ambassador Ron Prosor said Hamas was using ambulances filled with children “to move their terrorists around Gaza.”

He said Hamas “lives by violence and celebrates death. I want to be clear, our forces are fighting in Gaza, but they are not fighting the people of Gaza.”

Thousands of Israeli soldiers crossed into the Palestinian territory on the 10th day campaign of heavy air bombardments to try to destroy Hamas’ rocket-firing abilities and the tunnels militants use to infiltrate Israel.

Jordan asked for Friday’s meeting after Israel launched a ground invasion of Gaza on Thursday.

Copyright 2014 The Associated Press.