The father of an Israeli hostage rescued during a military operation in Gaza died a day before he could be reunited with his son, a relative has said.

Almog Meir Jan, 22, was held in Gaza for eight months after being kidnapped from the Nova music festival on 7 October.

He was one of four hostages who were rescued from central Gaza on Saturday, in an air and ground raid that also killed scores of Palestinians.

In the months before Almog’s release, the health of his father Yossi deteriorated and he was “glued to the television”, his sister Dina told Israeli broadcaster Kan.

“He was worried that he (Almog) was in the hands of murderers and about what was happening to him and what he was going through,” Ms Jan said.

Yossi Jan is believed to have died of a heart attack.

“My brother died of grief and didn’t get to see his son return,” Dina Jan said.

The rescue of Almog Jan and three other hostages was met with jubilation and relief in Israel, as Prime Minister Benjamin Netyanhu praised special forces for operating “creatively and bravely”.

But the humanitarian toll of the operation, which included a barrage of Israeli airstrikes, has sparked condemnation.

Gaza’s Hamas-run health ministry said 274 people were killed in the operation. If confirmed, it would make it one of the deadliest days in Gaza since the beginning of the conflict.

A Israel Defense Forces (IDF) spokesperson said the death toll was fewer than 100.

Qatar’s Prime Minister called for an intensification of global pressure on Israel to stop its “barbaric aggression” in Gaza, during a summit in Doha on Sunday.

The European Union’s top diplomat, Josep Borrell, condemned the killings as “another massacre of civilians”.

An Israeli minister said that instead of condemning Hamas for hiding behind civilians, the EU had condemned Israel for saving its citizens.

Israeli forces, backed by air strikes, fought intense gun battles with Hamas in the Nuseirat area, in what the Israel Defense Forces called a “high-risk, complex mission” based on “precise” intelligence.

In addition to Almog Meir Jan, hostages Noa Argamani, 26, Andrei Kozlov, 27, and Shlomi Ziv, 41, were rescued during the operation.

Some 116 people kidnapped in October remain in captivity. More than a third of them have already been confirmed dead, but that number is thought likely to be higher.

Benjamin Netanyahu visited the four returned hostages in hospital, telling one “we didn’t give up on you for one moment”.

“We expect Hamas to release them all. But if they don’t, we will do whatever it takes to get them all back home,” Mr Netanyahu said outside hospital.

On Sunday, Gaza’s Hamas-run health ministry said 37,084 people had been killed since the beginning of the conflict.