Israel is accused of “brutally assaulting” and injuring Marwan Barghouti, the most prominent Palestinian detainee in Israeli custody, according to Palestinian prisoner support groups.

Barghouti was assaulted on September 9 while held in solitary confinement in Israel’s Megiddo Prison , the Commission for Detainees and Ex-Detainees Affairs and the Palestinian Prisoner’s Society said in a joint statement on Monday.

As a result of the assault, Barghouti, called the “Palestinian Nelson Mandela” by his supporters, was left with numerous injuries, mainly to the upper body, the statement said.

The Fatah politician, who has been in jail for more than two decades, suffered injuries on the head, ears, ribs, right arm and back, said the statement, which quoted a lawyer who was only able to gather the information after months of being barred from contacting prisoners.

Barghouti suffered bleeding in the right ear, which later turned into an infection as a result of medical negligence, according to the statement.

The 64-year-old was reportedly assaulted along with a group of other Palestinian detainees.

The commission said Palestinians are being held in “tragic conditions”, especially over the past year during the war in Gaza.

Intensified arrests

Israel has stepped up arrests in the occupied West Bank since it launched an ongoing deadly assault on the besieged Gaza Strip in October last year. It has also intensified its mistreatment of Palestinian prisoners held in detention.

Prisoner rights groups and the United Nations have shed light on the systematic abuse being committed against prisoners held in Israeli jails, including beatings, hunger, a halt in visitations and medical negligence.

In its statement, the commission said it perceives the assaults against Barghouti and other prominent Palestinian figures in detention as an attempt to “assassinate” them.

Barghouti is extremely popular among Palestinians with polls suggesting that he could win the Palestinian presidency.

He has been subject to at least two other previous attacks, the statement said.

Barghouti was a prominent leader in the first and second Intifadas (uprisings) and was convicted by an Israeli court on five counts of murder in 2004, two years after he was imprisoned.

Israel accused Barghouti of having founded the Al-Aqsa Martyrs Brigades, a Fatah-aligned coalition of Palestinian armed groups, in the early 2000s – which he denied – and indicted him on 26 charges of murder and attempted murder attributed to the brigades.

He was sentenced by an Israeli court to five cumulative life sentences, plus 40 years for attempted murder and membership in a “terrorist” organisation.

Barghouti offered no defence, refusing to recognise the authority of the Israeli court.

According to Addameer, a Palestinian rights and prisoner support group, more than 10,000 Palestinians are currently held in Israeli jails with at least 3,390 of them held under administrative detention, a widely criticised practice in which they are held without charge or trial.