Hamas said in a statement on Saturday that the British-Israeli hostage Nadav Popplewell had died of wounds that he sustained in an Israeli airstrike more than a month ago.

Popplewell, 51, was a captive taken from Nirim kibbutz and a video previously released by Hamas’s armed wing, the Ezzedine al-Qassam Brigades, showed him displaying visible signs of physical abuse.

Popplewell and his mother, Channah Peri, 79, were abducted on 7 October from their residence in Nirim kibbutz, while his older brother, Roi, perished in the assault.

Peri was freed on 24 November.

In a statement released by the Hostages and Missing Families Forum headquarters, the family of Popplewell requested “that the recently released Hamas video not be published or used”.

The forum stated: “Every sign of life received from the hostages held by Hamas is another cry of distress to the Israeli government and its leaders. We don’t have a moment to spare! You must strive to implement a deal that will bring them all back today – the living to rehabilitation and the murdered to burial.”

Described by the campaign group as “generous and compassionate”, Popplewell was also known for his keen interest in science fiction literature.

A spokesperson for the Foreign Office told PA media that they are “urgently seeking more information following the release of this video. Our thoughts are with his family at this extremely distressing time.”

“The UK government has been working with partners across the region to secure the release of hostages, including British nationals. We will continue to do all we can to secure the release of hostages.”

The unprecedented abduction of approximately 250 individuals into the Gaza Strip occurred on 7 October during the assault by Hamas militants on southern Israel. According to Israeli authorities, 128 individuals are reported to remain in captivity within the Palestinian territory, with 36 confirmed as dead.

The video was released on a day when a series of demonstrations are expected to take place across the country, with families of hostages demanding the release of their loved ones held by Hamas in Gaza and early elections.

Israeli officials told the Ynet news site that hostage and ceasefire negotiations between Israel and Hamas had not completely broken down. Indirect talks would resume “if there are answers from Hamas that we can work with”, the officials told the site.

Hamas said on Friday that efforts to find a deal on a truce were back at square one after Israel rejected a plan from international mediators, while the White House expressed its commitment to try keeping the sides engaged “if only virtually”.