RAMALLAH: On Monday human rights researcher Ayman Nasser was denied bail by an Israeli military court, Addameer, a prisoner rights organization, said in a press release. The court ruled that he must remain in detention until the conclusion of his trial. Nasser's next hearing is scheduled for December 17th and has been held for 49 days. 42-year-old Nasser was initially arrested during a raid on his home in Saffa on October 25th, after which he was placed in a 39-day interrogation, during which some days spanned 20 consecutive hours, Addameer said. His pre-existing health conditions, notably an inflamed spine and ulcerous colon, have significantly worsened while in detention. Last week, after over a month of detention without charges, the military court accused Nasser of participating in solidarity protests for hunger strikers and attending a commemoration event for the late Popular Front for the Liberation of Palestine leader Abu Ali Mustafa, assassinated by Israel in 2001 in Ramallah. Addameer denies the legitimacy of these charges, arguing that Nasser “is accused of participating in demonstrations that are attended by all sectors of society, as they are annual commemorations that take place in the streets and public squares." Nasser is an employee of Addameer, who maintains that he is being held solely for his defense of prisoner rights. The organization also accuses Israel of violating the United Nations Universal Declaration of Human Rights by imprisoning a defender of human rights. The press release stated: According to the United Nations Declaration on Human Rights Defenders, Ayman Nasser's detention is illegal by international law standards. Article 12.1 states that “everyone has the right, individually and in association with others, to participate in peaceful activities against violations of human rights and fundamental freedoms. Last month Human Rights Watch demanded that Israel “stop harassing Addameer employees." As recently as November this year, 4,520 Palestinians are in Israeli detention centers, 164 of which are children. 156 are in administrative detention, a draconian practice in which prisoners are not charged and “secret evidence" is used against them. The Palestinian Authority minister of prisoner affairs announced that prisoners in Israeli military prisons plan to launch a mass one-day hunger strike on Tuesday, Ma'an News Agency reported. The strike is being conducted in solidarity with three hunger strikers whose health conditions are rapidly deteriorating.