RAMALLAH, Palestine

Thousands of Palestinians on Wednesday took to the streets across the Israeli-occupied West Bank to commemorate Palestinian Prisoners' Day, which is marked on April 17 of each year.

In the West Bank city of Nablus, thousands of Palestinians marked the occasion by waving Palestinian flags and carrying images of imprisoned loved ones.

Similar rallies were seen in Ramallah, Jenin, Bethlehem, Hebron (Al-Khalil), Tulkarm and Qalqilya, where demonstrators demanded the immediate release of Palestinians languishing in Israeli detention facilities.

Palestinians first began marking Prisoners' Day in 1974, when the Palestinian National Council adopted April 17 as a national -- and international -- day on which to show solidarity with Palestinian detainees.

According to the Palestine Liberation Organization (PLO)’s committee for detainees and ex-detainees, some 5,700 Palestinians are currently being held in Israeli prisons, including numerous women and children and a handful of lawmakers.

Over a million Palestinians have been held in Israeli jails -- for varying lengths of time -- since 1967, when Israel occupied the West Bank (including East Jerusalem) and the Gaza Strip, according to the PLO.

Since 2000, Israel is estimated to have detained over 10,000 Palestinian children in the West Bank, East Jerusalem and Gaza Strip.

Over 60 percent of children detained are reportedly subject to some form of physical and/or psychological torture by their Israeli captors.

Some 500 Palestinians are currently being held under Israel’s policy of "administrative detention", in which suspects can be held without trial or charge for renewable six-month periods.

The policy was first established by the British during the British Mandate in Palestine from 1923 to 1948.

According to the Palestinian Prisoners Association (PPA), a total of 218 Palestinians have died in Israeli custody since 1967.

Of these, seven were reportedly shot, 72 were tortured to death, and 63 died due to a lack of medical attention.

“Eighty-three others died as the result of premeditated murder or extrajudicial execution immediately after arrest,” PPA head Qadura Fares told Anadolu Agency.