The Israeli military says it is investigating, but could not refute or confirm claims of casualties in separate incidents.
Hamas's armed wing said one Israeli captive was killed in Gaza and two female captives were wounded in a separate incident, days before a new round of ceasefire talks proposed by the United States, Egypt and Qatar.
Qassam Brigades spokesman Abu Obeida said in a statement on Telegram on Monday that the Israeli captive was killed by his guards.
Attempts are being made to save the lives of the two seriously injured, he said, adding that a committee had been formed to investigate and further details would be announced.
Israeli army spokesman Daniel Hagari said they were investigating the matter. “At this point, we do not have any intelligence information… that would allow us to refute or confirm Hamas’s claims,” Hagari said in a post on X.
Protesters in Israel have gathered weekly to demand a ceasefire agreement that would allow the return of the captives. Prime Minister Benjamin Netanyahu's government has been criticised for failing to finalise the deal and for escalating tensions with Hezbollah in Lebanon.
Border clashes between the Lebanese group and Israeli forces, which have occurred almost daily since the conflict in Gaza erupted in October, have intensified. Hezbollah commander Fuad Shukr was killed in Beirut, hours after the assassination of Hamas leader Ismail Haniyeh in Tehran.
The United Nations Security Council (UNSC) is due to hold an emergency meeting on Tuesday following an Israeli attack on a school-turned-shelter in Gaza City that killed more than 100 Palestinians.
It will be the 24th special session of the Council since the war in Gaza began on 7 October.
So far, the United Nations Security Council has been unable to stop the conflict as the death toll in the enclave approaches 40,000. An emergency meeting was held on October 30 with a call to stop the fighting when the death toll was 8,000, but it has since soared to almost five times that figure.
On 24 May, the United Nations Security Council met to pass a resolution condemning the killing of UN staff and humanitarian workers. Since then, 15 other UN staff have been killed, as well as more humanitarian workers.
The Gaza Health Ministry says at least 39,897 people have been killed and 92,152 wounded since October. An estimated 1,139 people have been killed in Israel during Hamas-led attacks and more than 200 have been captured.
Qatar, Egypt and the United States have scheduled a new round of talks on a ceasefire in Gaza for August 15.
Hamas has called on mediators to present a plan based on a proposal put forward by US President Joe Biden, rather than trying to find a new deal.
U.S. Secretary of State Antony Blinken spoke with Turkish Foreign Minister Hakan Fidan on Monday “about the importance of Hamas' return to negotiations” this week to finalize “the framework for achieving an immediate and lasting ceasefire in Gaza and securing the release of all hostages,” the U.S. State Department said.
Fidan said Israel must avoid “provocative actions” that could increase tensions and said Hamas had shown a “constructive attitude” in previous truce talks, Turkey’s foreign ministry said.
He added that the assassination of Haniyeh in Iran on July 31 and the “ongoing massacre against Palestinians once again demonstrated Israel’s unwillingness to establish peace,” according to the Turkish ministry spokesman.
