The BBC has cited an official source, after the previous estimate from the weekend’s attack was originally placed at “more than 10”.
Only a few names have been confirmed among the deceased, including 20-year-old Nathanel Young, who had been a serving solider with the Israeli Defence Forces.
A former pupil at a Jewish mixed comprehensive school in north London, Mr Young had been moved to Israel and had been living in the Bayit Shel Benji home for lone soldiers in Raanana, which was north of Tel Aviv.
His family shared a post on Facebook saying they were “heartbroken” by the news, adding: “Our little brother Nathanel Young was tragically killed on the Gaza Border yesterday.”
Another British citizen who has been confirmed dead is Bernard Cowan, a Scottish grandfather who had relocated from Glasgow to near Gaza with his family.
In a statement his family said: “We are grieving the loss of our son and brother, Bernard Cowan, who was horrifically murdered on Saturday during the surprise terrorist attack on Israel by Hamas.
“We ask for privacy at this time while we process this huge loss to our family, both at home and in Israel, and to the Jewish community in Glasgow where he will be sorely missed.”
Also believed to have been killed is British photographer Daniel Darlington, whose sister shared on social media that he had been “murdered by terrorists” in Nir Oz on Saturday morning.
He died alongside his German friend Carolin, with his last Instagram posts showing the pair cycling and taking photographs of the sunset in southern Israel.
Shelley Darlington said: “Only days before he was riding his bike, laughing, taking photos of sunsets and enjoying life’s simple pleasures in our beautiful kibbutz.
“He was meant to leave for Tel Aviv the night before but decided to stay one more day to explore the kibbutz with his friend – a decision that has irrevocably changed all our lives forever, and one that cost him his life.”
Among those reported missing is Jake Marlowe, who was working as a security guard at a music festival near the Gaza border which was overrun with Hamas gunmen.
A carpenter by trade, he had been employed at the Nova music festival and is among the dozens of attendees who are missing, kidnapped or presumed dead.
Rescue services retrieved 260 bodies from the site with work currently ongoing to identify the remains of all those killed in the massacre.
“He last spoke to his mother at 4.30am UK time, saying he saw rockets [fired from Gaza] and that he even filmed it,” Daniel Aboudy, a friend of Mr Marlowe, told The Independent from London. “Then 45 minutes later they spoke briefly but since then his phone hasn’t rung.”
In another voice message sent to a friend, Mr Marlowe said that he was desperately trying to take people to safety on a quad bike.
Over the course of their unprecedented incursion into Israeli territories over the weekend, Hamas militants captured a number of hostages who are believed to currently be in Gaza.
They include an 85-year-old grandmother who was taken from her home without her medication, and a young festival-goer Noa Argamani, who was captured on the back of a motorbike while screaming for help.
President Joe Biden confirmed on Tuesday that American citizens are among the hostages and that 14 Americans have been killed in the fighting.
In retaliation, airstrikes have pounded neighbourhoods in Gaza with residential buildings and mosques turned to rubble.
The war has since claimed the lives of 2,100 people on both sides, while Israel has ordered a “complete siege” of the Gaza Strip, which is home to 2.3 million people.
This include the blockade of electricity, fuel, food and water while hospitals in the besieged enclave are said to be “at capacity” with only 10 to 12 hours of fuel left.