A woman sits at an installation recreating the war room where five female surveillance and observation soldiers from the Nahal Oz military who were kidnapped on the day of the Hamas October 7 attack on Israel, at the hostage plaza in Tel Aviv, on October 15, 2024. [AFP]

An adviser to Al-Qaeda's likely current leader is calling for Hamas to release its Israeli hostages held in Gaza, according to an American jihadist monitoring organisation, SITE.

The online declaration was made Friday by Mustafa Hamid, also known as Abu Walid al-Masri, who is father-in-law to Saif al-Adel, the man widely believed to now head Al-Qaeda, according to SITE.

In it, Hamid claimed the attention given to recovering the Israeli hostages, both dead and alive, was overshadowing the fate of Palestinian prisoners being held by Israel.

He also hailed Yahya Sinwar, Hamas's leader whom Israel announced a day earlier it had killed. Sinwar was the mastermind of the October 7, 2023 attacks on Israel that triggered the ongoing war in Gaza.

Hamas must now "immediately" return the hostages and their bodies, and "this file must be closed and not opened again, as we know its consequences," according to the statement.

"No one cares about the Palestinian prisoners, neither in the media, in negotiations, nor in demonstrations," it said.

Hamas grabbed a total of 251 hostages in its October 7, 2023 attacks. Since then, several have been found dead, and some were released in a short-lived December ceasefire, leaving 97 still in the hands of the Islamist Palestinian group.

Al-Qaeda, held responsible for the September 11, 2001 attacks in the United States, was the target of the American-led invasion of Afghanistan, where it was traditionally based.

Its then-leader Osama bin Laden was killed by US special forces in neighbouring Pakistan in 2011. Bin Laden's successor, Ayman al-Zawahiri, was killed by a US drone strike in July 2022.

The core Al-Qaeda organisation survives, and its de facto leader is believed to be Saif al-Adel, a former Egyptian special forces lieutenant colonel whose presence has been reported in Iran.

Several experts consulted by AFP say Hamid is close to higher-ups in the core Al-Qaeda organisation.

The group, which has spawned regional affiliates in Syria, Yemen, Somalia and Mali, has little leverage over Hamas, which is backed by Iran.

Hamas on Friday vowed not to release any hostages under the Gaza war ends.

Analysts said that, with no successor to Sinwar named and a vacuum in Hamas's leadership, it would be difficult to find someone to negotiate their release.