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

As fighting between Israel and Hamas resumes, Israel's "relentless bombardment" in Gaza on Friday has been "utterly terrifying" -- and has had an immediate impact “on the faces of children," UNICEF spokesperson James Elder told ABC News.

"I feel I was starting to see childhood return when you chat to them -- that’s been replaced by fear again," Elder said. "There’s a trauma which returns very quickly."

Elder described seeing "children lying on the floor with limbs missing." He said some children who had already been injured were being moved around hospitals to make room for other casualties to come in.

He said sanitation "has broken down" and Gaza’s hospitals are now "on life support."

“Disease threatens just as many children" as the bombings, he said.

Over the last seven days, aid has been reaching Gaza, he said, but, "seven days was never ever enough.”

Elder said he’s "terrified" that if the fighting continues for even another couple of weeks, “many, many more thousands of people" could be killed.

3:40

The Fight For Humanitarian Aid In Gaza

ABC News' Phil Lipof spoke with UNICEF Spokesperson James Elder about the aid getting into Gaza and what people on the ground need the most.

ABCNews.com

-ABC News' Tom Soufi Burridge, Zoe Magee, Angus Hines and Nicky De Blois

As a truce ended between Israel and Hamas on Friday, both sides traded blame for reigniting the war.

Israel accused Hamas of violating the cease-fire by firing rockets toward Israeli territory just after 7 a.m. local time, as negotiations failed to further extend the truce. The Israeli military has since resumed combat in the Hamas-ruled Gaza Strip, with ground, air and naval forces striking more than 200 "terror targets" in the north and south thus far, according to the Israel Defense Forces.

Meanwhile, Hamas accused Israel of "persistently rejecting" all its offers to release more hostages in Gaza amid negotiations to extend the cease-fire agreement on Thursday night. Hamas alleged that it had offered to hand over more Israeli detainees, including the elderly, as well as the bodies of those who have died in captivity, which the militant group claimed was a result of previous Israeli bombings.

"However, the [Israeli] occupation, driven by a predetermined decision to resume criminal aggression, remained unresponsive," Hamas said in a statement.

-ABC News' Morgan Winsor

An Israeli kibbutz confirmed Friday the death of three of its residents who were taken hostage by Hamas during the Oct. 7 attack.

Kibbutz Nir Oz announced that 85-year-old resident Aryeh Zalmanovich has died in Hamas captivity in the Gaza Strip. Zalmanovich was one of the founders of the kibbutz, which is located in southern Israel near the border with Gaza.

“Father of two sons and grandfather of five grandchildren. Aryeh was a man of the land all his life who was engaged in agriculture and field crops,” the kibbutz said in a statement. “A man of books and has a wide knowledge of history and knowledge of the country.”

Gaza's militant rulers, Hamas, released a video in mid-November that appeared to show Zalmanovich looking ill. The group claimed he had later died.

Kibbutz Nir Oz also announced that 54-year-old resident Ronen Engel has died in Hamas captivity in Gaza. The kibbutz described Engel as a "photographer, MDA volunteer and motorcycle enthusiast." His wife and two daughters were also kidnapped to Gaza on Oct. 7 and released this week, according to the kibbutz.

A third resident of kibbutz Nir Oz, 56-year-old resident Maya Goren, was also confirmed to have died in Hamas captivity in Gaza. Her husband was among those killed on Oct. 7, according to the kibbutz.

"Maya was a hardworking and dedicated kindergarten teacher, and gave loving care to the kibbutz children for many years," the kibbutz said in a statement.

-ABC News' Yael Benaya and Morgan Winsor

Israel will no longer hold fire as negotiations with Hamas progress, an Israeli security source told ABC News on Friday.

The source said Israeli forces will only cease-fire for 24 hours if Hamas sends a list of at least 10 hostages to be released, the list is approved by Israel and everyone on that list is safely returned home.

-ABC News' Matt Gutman