Some 4,000 mourners turned out Friday for the West Bank funeral of a man whose controversial death in an Israeli jail earlier this week has incensed the Palestinians.

Mourners crowded around the body of Raed al-Jaabari, which was wrapped in a Palestinian flag, shouting in grief during the funeral procession in his hometown of Hebron, in the southern West Bank, an AFP correspondent said.

The Palestinians said on Thursday that Jaabari, 35, had died from a severe blow to the head, and blamed Israel for his death, but Israeli authorities said he hanged himself.

"It's a crime, he was killed. The coroners confirmed it, he died from a violent blow to the head," former Palestinian prisoners minister Issa Qaraqe, who attended the funeral, said in his eulogy to Jaabari.

Jaabari's body was taken for post-mortems by both Israel and the Palestinians after his death on Tuesday, with Israel not yet publishing its findings.

The Israel Prisons Service has said that Jaabari hanged himself in a bathroom at Eshel prison in southern Israel and died en route to hospital.

Israel has appointed a judge to investigate the death.

IPS figures show that as of July 31 there are 5,383 Palestinians being held by Israel for security offences, among them 446 without charge under so-called administrative detention orders.