Vice President Kamala Harris and second gentleman Doug Emhoff spoke with the parents of Hersh Goldberg-Polin, an American-Israeli hostage who was found dead in Gaza on Saturday along with five other Oct. 7 hostages, according to the Israel Defense Forces.

The vice president and her husband called parents Rachel Goldberg and Jon Polin on Sunday to "express our condolences following the brutal murder of their son by Hamas terrorists," Harris said in a statement on X.

"My heart breaks for their pain and anguish," Harris continued.

"I told them: As they mourn this terrible loss, they are not alone. Our nation mourns with them," Harris said.

Protesters took to the streets of Tel Aviv Sunday night, demanding a cease-fire agreement and the release of the remaining hostages being held by Hamas terrorists.

The demonstration came a day after Israel Defense Forces recovered the bodies of six hostages in tunnels under the city of Rafah in the Gaza Strip.

Protesters were seen waving Israeli flags as they demanded a cease-fire agreement, chanting "Deal. Now."

-ABC News' Victoria Beaule

At least six people were killed on Sunday when Israel Defense Forces conducted an airstrike on a school in Gaza City, according to Gaza Civil Defense.

The IDF said in a statement that the strike was aimed at Hamas terrorists they allege were operating a command-and-control center inside the Safad school to plan and carry out terrorist attacks against the IDF and Israel.

"Prior to the strike, numerous steps were taken to mitigate the risk of harming civilians, including the use of precise munitions, aerial surveillance, and additional intelligence," the IDF said in a statement.

The Gaza Civil Defense confirmed the Safad school was hit in the IDF strike, but said the school houses displaced people from the Al-Zeitoun area east of Gaza City.

-ABC News' Victoria Beaulé

Secretary of State Antony Blinken spoke Sunday with the parents of U.S.-Israeli citizen Hersh Goldberg-Polin, who Isreal Defense Forces found fatally shot Saturday along with five other hostages who were being held in Gaza tunnels by Hamas terrorists, according to a State Department spokesperson.

In his phone conversation Sunday with Rachel Goldberg and Jon Polin, Blinken offered "deep condolences for the death of their son," said State Department spokesperson Matt Miller said.

-ABC News' Shannon Kingston

The Israeli military announced Tuesday that it had rescued an Arab citizen of Israel who was among scores of people abducted in the Hamas-led Oct. 7 terror attack.

Qaid Farhan Alkadi, 52, from the Bedouin town of Rahat in southern Israel, was rescued "in a complex operation in the southern Gaza Strip," according to Israeli authorities. He is the eighth Israeli hostage to be rescued alive from Gaza by the Israel Defense Forces and the first hostage to be rescued alive from a tunnel in the war-torn territory, an Israeli official said.

An Israeli source told ABC News that Alkadi is currently at Soroka Medical Center in the southern Israeli city of Beersheba.

In a joint statement, the IDF and Israel Securities Authority said Alkadi "is in a stable medical condition and is being transferred for medical checks at a hospital." A spokesperson for the Soroka Medical Center told ABC News he "is fully conscious and in good general condition." The spokesperson added that Alkadi had "already met with a family member with great excitement."

The Hostages Families Forum -- a group representing family members of those taken hostage on Oct. 7 -- said in a statement that it "commends the rescue." It described Alkadi's return home as "nothing short of miraculous," adding: "We must remember: military operations alone cannot free the remaining 108 hostages, who have suffered 326 days of abuse and terror. A negotiated deal is the only way forward."

Israeli President Isaac Herzog wrote on X: "This is a happy moment for the State of Israel and for Israeli society as a whole. I wish for the immediate and speedy return of our 108 abductees who are brutally held captive in Gaza."

Prime Minister Benjamin Netanyahu's office said the leader had spoken with Alkadi by phone. "The prime minister congratulated Farhan and told him that the entire Israeli people are excited by his release," the office said in a statement. "The prime minister clarified in the conversation that he will continue to do everything to return all our abductees home."

Defense Minister Yoav Gallant said the "bold and determined" operation "joins a series of impressive operational activities, which bring us closer to achieving all the goals of the war."

-ABC News' Morgan Winsor, Jordana Miller, Dana Savir and Anna Brund