The Israeli military said Wednesday that it spoke with members of the Bibas family following a claim by the military wing of Hamas, the Al-Qassam Brigades, that three members of the Israeli family — Shiri Bibas and her two children, 4-year-old Ariel and 10-month-old Kfir — were killed in Israeli strikes on the Gaza Strip.

Israel Defense Forces spokesperson Daniel Hagari said the IDF was "examining the reliability of the information." 

The armed wing of Hamas, which the U.S. and Israel consider a terrorist organization, said on social media Wednesday that the three civilians were killed previously by Israel Defense Forces strikes, but gave no additional information on their alleged deaths. CBS News could not independently verify the claim.

Hagari said "IDF representatives spoke with the members of the Bibas family, informed them of the publication, and are accompanying them at this time." He also said "the responsibility for the safety of all the abductees in the Gaza Strip lies fully with the terrorist organization Hamas."

The Bibas family said in a statement it had heard the claims, and was "waiting for the information to be confirmed and hopefully refuted by military officials."

The Bibas children have become powerful symbols of the plight of the roughly 160 people still believed to be held captive in Gaza after Hamas militants' brutal terror rampage across southern Israel on Oct. 7.

Video clips seemingly captured by the militants showed the Bibas children and both of their parents being seized during the Hamas raids on Israeli communities near the Gaza border during the group's unprecedented attack.

Hamas has previously claimed hostages it was holding were killed by Israel's missile and airstrikes on Gaza in the wake of the Oct. 7 attack, but it has yet to show any proof of those killings. Some who have previously been declared dead have been found to be alive, like Hanna Katzir, who was released this week after the Gaza militant group Islamic Jihad said she had been killed. Several people seized by Hamas have been found dead in Gaza, but the IDF has accused Hamas of killing them.

On Tuesday night in Tel Aviv, hundreds of people rallied to demand that Hamas release all the remaining hostages. Many of the demonstrators — including an aunt of the Bibas children — wore or carried images of the young boys, or orange balloons to symbolize solidarity with the red-headed youngsters.

Yifat Zailer, a cousin of Shiri Bibas, said on "CBS Mornings" Wednesday – before news of Hamas' claim about the family's death – that the kids got their hair color from their grandfather, who was killed by Hamas militants alongside his wife on Oct. 7.

"Everything is surreal, a nightmare," she said. 

Hamas issued its claim Wednesday with just hours left in an extended, short-term cease-fire deal that has seen fighting between Israel and Hamas paused since Nov. 24.

Another 16 hostages, including an American woman, were released by Hamas on Wednesday, following 12 who were freed Tuesday night, bringing the total number freed by the group under the terms of the truce to about 100. Israel, in return, has released some 210 Palestinian prisoners.

Hamas expressed interest this week in negotiating a new agreement with Israel to extend the pause in fighting to enable the release of more hostages, but Israel has not confirmed any terms being discussed. The negotiations are taking place in Doha, Qatar, with the Qataris acting as intermediaries between the warring sides.

None of the recently released hostages have spoken to the media. Many are still recovering in the hospital. But their relatives have begun to share disturbing details.

"They didn't see light, sunlight," Sharon Calderon, the aunt of two recently freed hostages — 16 year-old Sahar and 12 year-old-Erez — told CBS News.

She said the children had been able to see a TV, so they knew their mother was alive during their captivity, and added that it was "very good for them to know that she's alive."

Efrat Michikawa, the niece of another hostage released as part of the deal, Margalit Moses, said her aunt was "the same but not the same, because nothing will go back to what life was before."

In the videos of Hamas militants handing hostages over to the Red Cross, the militants have portrayed themselves as caring and gentle. Some hostages have said they were treated with decency, but there have also been distressing stories.

"When he got to Gaza, all the civilians beat him up," the aunt of 12-year-old Eytan Yahalomi told French television, saying he was beaten when he arrived in Gaza and forced to watch videos of the Oct. 7 massacres.

She also alleged that the militants had pointed guns at child hostages when they cried.

Holly Williams and Sarah Lynch Baldwin contributed to this article.

In:
• Hamas
• Israel
• Gaza Strip

Tucker Reals is cbsnews.com's foreign editor, based in the CBS News London bureau. He has worked for CBS News since 2006, prior to which he worked for The Associated Press in Washington D.C. and London.