The brother of an Israeli hostage held in the Gaza Strip has told the BBC that a Hamas video showing him emaciated and weak is a “new form of cruelty” that has left his parents shattered.

Hamas released the footage of Evyatar David, 24, on Saturday, drawing strong condemnation from Israel and Western leaders.

“He’s a human skeleton. He was being starved to the point where he can be dead at any moment, and he suffers a great deal. He barely can’t speak, he barely can move,” David’s brother Ilay said in an interview on Monday.

In the video, Evyatar says: “I haven’t eaten for days… I barely got drinking water.” He is seen digging what he says will be his own grave.

Hostages’ families have urged Prime Minister Benjamin Netanyahu to prioritise their release as reports suggest he might be planning to expand the military campaign.

The footage of Evyatar was released after Palestinian Islamic Jihad published video of another hostage, Rom Braslavski, thin and crying.

Both men were abducted from the Nova music festival during the Hamas-led attack on southern Israel on 7 October 2023.

They are among 50 hostages still being held in Gaza, 20 of whom are believed to be alive.

Ilay David said his father had barely recognised his son Evyatar’s voice on the video and had not been able to sleep. He said his mother cried all day.

“Seeing those images of my brother as a human skeleton, we understood it’s, it’s, it’s a new kind of cruelty,” Mr David said. “It’s the lowest you can get.”

He called on world leaders to unite to save him and other hostages “from the cruel, twisted hands of Hamas”.

“So we have to be so focused on delivering the message, which is, Evyatar is dying, we need to give him medicine, to give him food, proper food, and you need to get this treatment now, or else will die.”

Hamas’s armed wing has denied it intentionally starves prisoners, saying hostages eat what their fighters and people in Gaza eat.

After the hostages’ videos were released, Netanyahu spoke with their families, telling them that efforts to return all the hostages “will continue constantly and relentlessly”.

But an Israeli official – widely quoted by local media – said Netanyahu was working to free the hostages through “the military defeat of Hamas”.

The possibility of a new escalation in Gaza may further anger Israel’s allies who have been pushing for an immediate ceasefire as reports of Palestinians dying from starvation or malnutrition cause shock around the world.

The main group supporting hostages’ families condemned the idea of a new military offensive saying: “Netanyahu is leading Israel and the hostages to doom.”

That view was pointedly made in a letter by some 600 retired Israeli security officials sent to US President Donald Trump urging him to pressure Israel to immediately end the war in Gaza.

“Your credibility with the vast majority of Israelis augments your ability to steer Prime Minister [Benjamin] Netanyahu and his government in the right direction: End the war, return the hostages, stop the suffering,” they wrote.

The group included former Mossad chief Tamir Pardo, Ami Ayalon, former chief of Shin Bet – Israel’s domestic secret service agency – former Prime Minister Ehud Barak, and former Defence Minister Moshe Yaalon among others.

“It is our professional judgement that Hamas no longer poses a strategic threat to Israel,” they said.

“At first this war was a just war, a defensive war, but when we achieved all military objectives, this war ceased to be a just war,” said Ayalon.

The former top leaders head the Commanders for Israel’s Security (CIS) group, which has urged the government in the past to focus on securing the return of the hostages.

“Stop the Gaza War! On behalf of CIS, Israel’s largest group of former IDF generals and Mossad, Shin Bet, Police, and Diplomatic Corps equivalents, we urge you to end the Gaza war. You did it in Lebanon. Time to do it in Gaza as well,” they wrote to the US president.

Israel launched a devastating war in Gaza following Hamas’s 7 October attack in which about 1,200 people were killed and 251 taken into Gaza as hostages.

More than 60,000 people have been killed as a result of Israel’s military campaign in Gaza since 7 October, the Hamas-run health ministry says.

On Monday, the ministry reported that at least 94 people had been killed in Gaza in the past day, including dozens it said had died in Israeli strikes.

The territory is also experiencing mass deprivation as a result of heavy restrictions imposed by Israel on what is allowed into Gaza. The ministry says 180 people, including 93 children, have died from malnutrition since the start of the war.

Such reports have become almost daily in recent months but are hard to verify as international journalists, including the BBC, are blocked by Israel from entering Gaza.

UN-backed agencies have said the “worst-case scenario of famine is currently playing out” in Gaza.