The Israeli military says the body of an Israeli hostage held by Hamas in the Gaza Strip has been recovered in a joint operation with the Shin Bet security service.

A statement said Itay Svirsky, 38, who was kidnapped from Kibbutz Be’eri during Hamas’s 7 October 2023 attack on Israel, was “murdered in captivity by his captors”.

Hamas said in January that Svirsky and another hostage, Yossi Sharabi, 53, had been killed by Israeli air strikes.

Earlier, the military said an investigation had concluded that the most plausible explanation for the deaths of six other hostages found dead in a tunnel in Gaza in August was that they were shot by Hamas “close” to the time of an Israeli air strike.

Troops recovered the bodies of Yagev Buchshtab, 35, Alexander Dancyg, 76, Avraham Munder, 79, Yoram Metzger, 80, Chaim Peri, 79, and Nadav Popplewell, a 51-year-old British-Israeli dual national, along with those of six Hamas fighters, in the southern Khan Younis area.

The military said it was “highly probable” the hostages’ deaths were related to a February strike on a nearby underground site that targeted Hamas commanders.

Pathologists found indications of gunshots on the hostages’ bodies, while no gunshot wounds were found on the fighters’ bodies, it added.

Due to the extended time that had passed “it was not possible to determine with complete certainty the precise cause of death of the hostages or the exact timing of the gunfire”, according to the military.

“According to the most plausible scenario, the terrorists shot the hostages close to the time of the strike,” it said. “However, it is also possible that the hostages were shot by other terrorists post-mortem; it is even possible that the hostages were killed prior to the strike in the area.”

An Israeli military official told reporters that the military believed the six Hamas fighters were “were killed from secondary effects of our strike”, like lack of oxygen.

The military also stressed that it had “no information”, at the time of the strike that the hostages were in the underground site that was targeted or its vicinity.

“Had such information been available, the strike would not have been carried out,” it said, noting that it was preceded by the required planning and approval process.

There was no immediate comment from Hamas.

Buchshtab, Dancyg, Munder, Metzger, Peri and Popplewell were kidnapped from Kibbutz Nir Oz and Kibbutz Nirim on 7 October 2023.

About 1,200 people were killed by Hamas-led gunmen that day, while 251 others were taken back to Gaza as hostages.

The US, Egypt and Qatar have spent months working on a deal to secure the release of the 96 remaining hostages, 35 of whom are presumed dead, in return for a ceasefire in Gaza.

But the negotiations have stalled, with Hamas and Israel blaming each other for the impasse.

The Hostages and Missing Families Forum said the military investigation’s findings “serve as yet another proof that the lives of hostages face constant, daily danger”.

“Time is of the essence – many of the hostages are still alive and enduring impossible conditions of abuse, starvation and isolation,” it warned.

The forum called on US and the other mediators to “do everything necessary to achieve a deal for the hostages’ return”.

It separately welcomed the return of Itay Svirsky’s body for burial in Israel, saying it “provides crucial closure for his family”.

Israeli Defence Minister Israel Katz said in a statement on Wednesday that “pressure on the monstrous organisation known as Hamas is growing”.

“There is a chance that this time we will truly be able to advance a hostage deal.”

More than 44,500 people have been killed in Gaza since Israel launched a military campaign in response to the 7 October attack, according to the territory’s Hamas-run health ministry.

On Wednesday evening, at least 20 people had been killed by an air strike in the Israeli-designated “humanitarian area” in al-Mawasi, west of Khan Younis, according to medics and the Hamas-run Civil Defence Agency.

Civil Defence spokesman Mahmoud Bassal said a tented camp for displaced families was bombed and that the dead included five children.

The Israeli military said its aircraft targeted “senior Hamas terrorists” in the area.

Another 10 people were killed when Israeli strikes hit three houses in Gaza City, in northern Gaza, according to Mr Bassal.

Earlier, five people were killed in an Israeli strike on the urban Nuseirat refugee camp in central Gaza, medics said. Local media said four of the dead were children and that the strike had targeted a queue outside a bakery.

The Israeli military said it had struck a “terrorist target” in Nuseirat, without giving any details, according to the Associated Press.