Israel-Gaza updates: Israel says ground operation underway in southern Gaza

In Gaza, where the humanitarian crisis is worsening by the day, 68% of the people killed are women and children, while four out of five residents are displaced, according to U.N. Under-Secretary-General for Humanitarian Affairs and Emergency Relief Coordinator Martin Griffiths.

"I don't think I've seen anything like this before. It's complete and utter carnage," he told CNN on Sunday.

"Nobody goes to school in Gaza. Nobody knows what their future is. Hospitals have become a place of war, not of curing," Griffiths said.

"It's not just a crisis about Gaza. It's a crisis about humanity," Griffiths said. "War has become the option of the day, and the suffering that comes from it is astronomical."

Eleven more hostages who were abducted from Israel on Oct. 7 have been released and are in the custody of the Red Cross, an Israeli Defense Forces spokesperson said.

The 11 hostages released from Gaza Monday were dual citizens -- from Israel as well as France, Germany and Argentina -- while the 33 released Palestinians are comprised of 30 minors and three women, Qatari officials said.

Israel identified the returned hostages as 12-year-old Eitan Yahalomi, 51-year-old Karina Engel-Bart, 18-year-old Mika Engel, 12-year-old Yuval Engel, 34-year-old Sharon Aloni-Cunio, 3-year-old Yuli Cunio, 3-year-old Emma Cunio, 16-year-old Sahar Calderon, 12-year-old Erez Calderon, 16-year-old Or Yaakov and 12-year-old Yagil Yaakov.

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11 more hostages released from Gaza in exchange for 33 PalestiniansSixty-nine hostages have been released by Hamas, exchanged for 150 Palestinians released from Israeli prisons.

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The cease-fire between Israel and Hamas "has allowed for a surge of humanitarian assistance into Gaza," National Security Council spokesperson John Kirby noted.

Two-hundred trucks were dispatched to Gaza on Sunday -- the biggest convoy of aid since Oct. 7, Kirby said. Over 2,000 trucks have now entered Gaza, he said.

With two more days now added to the cease-fire, there's "the chance for dozens more trucks, and tens of thousands of more gallons of fuel, that can get into Gaza to people in need," Kirby said. "We're going to take advantage of every hour of every day that there's a pause to try to help the people of Gaza."

-ABC News' Cheyenne Haslett

President Joe Biden touted the extension of the humanitarian pause in Gaza, saying in a new statement that he has "remained deeply engaged over the last few days to ensure that this deal -- brokered and sustained through extensive U.S. mediation and diplomacy -- can continue to deliver results."

Fifty-eight hostages -- 40 Israelis and 18 foreign citizens -- have been released so far, including 4-year-old American-Israeli Abigail Idan. Abigail was released on Sunday, two days after her 4th birthday.

Biden said he "spoke with Abigail’s family following her release, and we are working closely with our Israeli partners to ensure she gets the care and support she needs as she begins to recover from this unspeakable trauma."

Biden also noted, "We are taking full advantage of the pause in fighting to increase the amount of humanitarian aid moving into Gaza, and we will continue our efforts to build a future of peace and dignity for the Palestinian people."

The president thanked leaders from Israel, Qatar and Egypt for their continued work, and vowed, "We will not stop until all of the hostages held by Hamas terrorists are released."

-ABC News' Molly Nagle