The Israel Prison Service announced late Saturday the death of a Palestinian detainee in an Israeli jail.

The prison authority, in a statement cited by the Jerusalem Post newspaper, said the deceased was 38 and was detained in 2005.

It did not, however, reveal his name but said he is affiliated with the Fatah group and an investigation will look into the circumstances of his death.

The Commission for Prisoners' Affairs of the umbrella Palestine Liberation Organization (PLO) identified the detainee as Tha'er Abu Asab, from Qalqilya, who was sentenced to 25 years in prison by Israeli authorities.

It added that since Oct. 7, six Palestinian detainees have died inside Israeli jails.

The commission warned that "the (Israeli) occupation is carrying out a systematic assassination against the (Palestinian) detainees."

Since Oct. 7, the Israeli army detained more than 2,850 Palestinians from areas across the occupied West Bank and East Jerusalem, which adds to the 5,200 Palestinians held in Israeli jails before that date.

Israel has killed more than 12,300 Palestinians in its air and ground attacks on the Gaza Strip since an Oct. 7 surprise offensive by the Palestinian resistance group, Hamas. The official Israeli death toll, meanwhile, stands at about 1,200.

*Writing by Ahmed Asmar