Israeli strikes throughout Gaza claimed the lives of 29 Palestinians, including young quintuplets, overnight and into Sunday, just as Anthony Blinken was arriving in Israel for peace talks.
The news comes on the heels of newborn twins killed in Gaza last week by an Israeli strike while their father registered the births.
U.S. officials, along with mediators from Egypt and Qatar, have said they are close to reaching a deal following two days of discussions in Doha.
Israeli officials have also expressed cautious optimism, according to the Associated Press.
On Sunday, however, Hamas released a statement accusing Israeli Prime Minister Benjamin Netanyahu of setting new conditions involving his refusal of a complete withdrawal of forces from Gaza.
The drawn-out proposal allegedly calls for a three-phase process in which Hamas would release all hostages abducted during its Oct. 7 attack, while in return, Israel would withdraw its forces from Gaza and release Palestinian prisoners.
Israel's war on Gaza has killed some 40,000 Palestinians since it launched its offensive following Hamas' October attack.
The vast majority of the enclave's 2.3 million residents are now displaced amid warnings of famine and polio outbreaks.
"It is as if we live a primitive life," said Sanaa Akela, a displaced Palestinian in the central town of Deir al-Balah, where sewage floods numerous streets.
The latest Israeli assault included a strike on a home in Deir al-Balah that killed a woman and her six children, according to a reporter from the AP.
Mohammed Awad Khatab said his daughter was a teacher, and his youngest grandchild was 18 months old. The others were 10-year-old quintuplets.
"The six children have become body parts. They were placed in a single bag," Khatab explained to reporters.
"What did they do? Will this provide security to Israel?" he asked.
Another strike in the southern city of Khan Younis killed four people from the same family, including two women.
Meanwhile, Israel continues to maintain that it only targets militants, and blames civilian deaths on Hamas, accusing militants of hiding in residential areas.
The Israeli bombardment has wiped out entire extended families and orphaned thousands of children, according to AP.
Following the targeted killing of two top militants last month, both initiated by Israel, negotiation efforts have heightened in urgency as promises of revenge from Iran and the Lebanese Hezbollah cause greater fear of a war across the Middle East.
An Israeli delegation was reported to have traveled to Cairo Sunday for further talks, while Blinken is due to meet with Netanyahu on Monday.
Blinken will also travel to Egypt on Tuesday for negotiations with officials there, said the State Department.
