At least four civilians were killed while in the custody of Hamas, just feet from where armed militants had been escorting them near the Gaza border, videos obtained and geolocated by CNN show.
One video from the kibbutz of Be'eri in southern Israel showed armed fighters with burned cars and a bulldozer in the background. Toward the end of the video, which was released on a Hamas-affiliated Telegram channel, four bodies can be seen on the ground.
Another video previously geolocated by CNN showed five Israeli civilians taken captive by armed militants in nearly the same spot.
A CNN analysis of the videos determined that the bodies, and the individuals being escorted by heavily armed militants, had matching clothes and hairstyles.
It is not clear what happened to the fifth hostage.
Be'eri lies just three miles from the eastern border of Gaza.
Alongside other communities close to Gaza such as Ofakim, Sderot, Yad Mordechai, Kfar Aza, Yated and Kissufim, it was among the first to be targeted by Hamas fighters as they launched Saturday morning's unprecedented and carefully coordinated killing and hostage-taking spree.
The community of Be'eri was "very badly hit," Israel Defense Forces (IDF) spokesperson Lt. Col. Richard Hecht said Monday during a briefing, more than 48 hours after Hamas launched the surprise attack.
Hecht said most Hamas militants in Be'eri had been killed, but Israeli troops were still there attempting to clear the area of any remaining fighters.
"We are still fighting. We thought this morning we would be in a better place," Hecht said.
As many as 1,000 Hamas fighters breached the border from Gaza, according to Israeli authorities, in an attack that has killed more than 700 Israelis, prompting retaliatory Israeli airstrikes and a formal declaration of war on Sunday.
More than 400 Palestinians have been killed, including 78 children, according to the health ministry in Gaza, and medical care has been complicated by Israel cutting power to the territory.
Hamas militants have taken more than 100 Israelis hostage, including high-ranking army officers, a spokesperson for the group claimed Sunday. It's believed they are in Gaza but their fate is unknown.
Another Palestinian armed group, Islamic Jihad, on Sunday said it is holding at least 30 hostages in Gaza. CNN is unable to verify the claims.
Israel authorities have said that dozens of Israelis are being held hostage in Gaza but have not confirmed exact numbers. In addition to Israeli captives, several other nationalities are believed to have been taken hostage.
Hecht said it was possible that Hamas fighters were still crossing into Israel from Gaza, adding that four fighting divisions had been deployed in the south.
He said around 20 breach points had been totally secured but other points were more vulnerable.
"There are some areas where we are still holding on with tanks and air cover. I can't deny the fact that there are still people coming in ... It's an ongoing fight," he said.
Clarification: This story has been updated to more accurately describe the communities near the Gaza border
