RAMALLAH, July 16 (Xinhua) -- Head of Palestine Liberation Organization (PLO) Detainees Affairs Commission said Tuesday that Nassar Majed Taqatqa, 31, who has been held in solitary confinement in the Israeli prison of Nitzan in the city of Ramleh, central Israel, was declared dead.

Qadri Abu Bakr, head of the commission, told reporters that the Israeli forces detained Taqatqa about a month ago after raiding his home in the village of Beit Fajjar, south of the occupied West Bank city of Bethlehem, and moved him to the Israeli prison of Al-Jalameh for interrogation, after which he was put in solitary confinement in Nitzan prison.

The commission head said the circumstances of Taqatqa's death are unclear yet, and his death cause remains unknown.

Jawad Thawabteh, member of the Fatah movement in Bethlehem, told official Palestinian news agency WAFA that the Israeli forces brought Taqatqa handcuffed to his family house about two weeks ago to search it and he was severely beaten before taking him back to prison.

The Palestinian Prisoner Club (PPC), a quasi governmental body providing legal assistance to prisoners, said in a press statement that Taqatqa was first detained on June 19.

His family was quoted as saying that he did not have any medical or health issues prior to his arrest.

The PPC said that with Taqatqa's death, the number of Palestinians died in Israeli custody since 1967 has risen to 220.

According to official data provided by the commission and the PPC, there are currently nearly 5,500 Palestinians in Israeli jails, including around 700 suffering diseases.

The causes of deaths in previous cases, said the PPC, included torture during investigation, medical negligence, oppression, gun fire by Israeli soldiers inside Israeli jails, willful killings and field executions right after arrest.