Over 1,600 Palestinian prisoners in Israeli jails are planning to begin an open-ended hunger strike on April 17, coinciding with Palestinian Prisoners Day, Ma’an News Agency reported on Saturday.

According to the Palestinian prisoners’ rights group Addameer, over 4,600 Palestinians are currently held in Israeli jails. More than 300 are held in administrative detention, meaning their imprisonment is overseen by the military without a formal trial or indictment.

Eight Palestinians are currently on hunger strike, according to Physicians for Human Rights; seven of them are in administrative detention. In recent months the tactic has proven effective both in drawing attention to Israel’s detention policies and in the release of prisoners.

Earlier this year, Khader Adnan’s refusal to eat for 66 days — while he was under administrative detention — drew international media attention until a deal was struck in February which granted his release. Adnan is due to be released on April 17.

Hana Shalabi, who was re-arrested in February after being freed as part of the Gilad Shalit prisoner exchange, struck a deal in late March to be deported to Gaza for three years in exchange for ending her 43-day hunger strike.