The most prominent Palestinian prisoner, Marwan Barghouti, was beaten unconscious by Israeli prison guards on 14 September, his family has said.

The 66-year-old - serving life for planning deadly attacks against Israelis - was allegedly assaulted by eight guards during a transfer between Ganot and Megiddo prisons.

The Israel Prison Service told the BBC: These are false claims (fake). The Israel Prison Service operates in accordance with the law, while ensuring the safety and health of all inmates.

Barghouti's son, Arab, told the BBC the family had received testimony from five separate detainees released this week who heard Barghouti's account of the attack. He stated the family was horrified.

Barghouti was allegedly handcuffed by the guards, put on the floor, kicked and beaten. They focused on the head area, they focused on the chest area and also on the legs, he said. He stayed unconscious for hours, he was bleeding, and he could hardly walk.

Arab shared his belief that the attack occurred during the transfer between prisons, as there were no surveillance cameras to capture it.

Barghouti is serving five life sentences plus 40 years after being convicted by an Israeli court in 2004 of planning attacks in which five civilians were killed.

The detainees who relayed details of the attack to the family were released as part of a recent hostage and prisoner exchange between Israel and Hamas.

Barghouti's name was at the top of a list of seven high-profile prisoners whose release Hamas had sought in exchange for the 20 living Israeli hostages but Israel refused to include him.

Many view Barghouti as a potential unifying figure for Palestinians, with consistent polls showing he is the most popular Palestinian leader, surpassing both current PA President Mahmoud Abbas and Hamas leaders in hypothetical elections.

Barghouti continues to represent a senior figure in the Fatah faction, which governs parts of the West Bank not under Israeli control, and has been in solitary confinement since October 2023.

Far-right Israeli National Security Minister Itamar Ben Gvir, in charge of the prison service, denied Barghouti had been assaulted but expressed pride in the deterioration of his prison conditions.

In August, a video surfaced of Ben Gvir taunting Barghouti in his cell, marking his first public appearance in years. The PA condemned the incident, with Vice-President Hussein al-Sheikh calling it the epitome of psychological, moral and physical terrorism.