DEIR AL-BALAH, Gaza Strip — Israeli strikes across Gaza killed 29 people including young quintuplets overnight and into Sunday, health officials said, as U.S. Secretary of State Antony Blinken arrived in Israel to try to seal a cease-fire deal that could help ease soaring regional tensions.

The U.S. and fellow mediators Egypt and Qatar have said they were closing in on a deal after two days of talks in Doha, with Israeli officials expressing cautious optimism. But Hamas in a statement Sunday accused Israeli Prime Minister Benjamin Netanyahu of setting new conditions, including his refusal of a complete withdrawal of forces from Gaza.

The evolving proposal calls for a three-phase process in which Hamas would release all hostages abducted during its Oct. 7 attack, which triggered the deadliest war fought between Israelis and Palestinians. In exchange, Israel would withdraw its forces from Gaza and release Palestinian prisoners.

The Israeli offensive has killed more than 40,000 Palestinians, according to local health authorities, displaced the vast majority of the territory’s 2.3 million residents and led experts to warn of famine and the outbreak of diseases like polio.

“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 flooded some streets.

Hamas-led militants killed some 1,200 people in the Oct. 7 attack and abducted around 250. Of those, some 110 are still believed to be in Gaza. More than 100 hostages were released in November during a weeklong cease-fire.

The latest Israeli bombardment included a strike on a home in Deir al-Balah that killed a woman and her six children, according to Al-Aqsa Martyrs Hospital. An Associated Press reporter there counted the bodies.

Mohammed Awad Khatab, the children’s grandfather, said his daughter was a teacher, and the youngest child was 18 months. The others were 10-year-old quintuplets, the hospital said.

“The six children have become body parts. They were placed in a single bag,” Khatab told reporters. “What did they do? Did they kill any of the Jews? … Will this provide security to Israel?”

Another strike east of Deir al-Balah killed at least four people, according to an AP journalist at the hospital. A strike in the northern town of Jabaliya hit two apartments, killing two men, a woman and her daughter, according to Gaza’s Health Ministry. Another two strikes in central Gaza killed nine people, according to Al-Awda Hospital. A strike in Nuseirat killed one person, the hospital said.

Late Saturday, a strike near the southern city of Khan Younis killed four people from the same family, including two women, according to Nasser Hospital.

Israel says it only targets militants and blames civilian deaths on Hamas because the group places fighters, weapons, tunnels and rockets in residential areas. But the Israeli bombardment has wiped out entire extended families and orphaned thousands of children.

Mediation efforts gained new urgency after the targeted killing of two top militants last month, both attributed to Israel, brought vows of revenge from Iran and the Lebanese Hezbollah, raising fears of all-out war across the Middle East.

An American official said Friday that mediators were beginning preparations for implementing the latest cease-fire proposal, and Netanyahu’s office expressed “cautious optimism” a deal could be reached.

An Israeli delegation was traveling to Cairo on Sunday for further talks, and Blinken will meet with Netanyahu on Monday. Blinken will travel to Egypt on Tuesday for meetings with officials there, the State Department said, and may stop in at least one other regional country.