In a duel within Israel's military court system, prosecutors filed charges against a prominent Palestinian academic days after a judge ordered him freed from internment, the army said late Sunday. Astrophysics professor Imad Barghouti, 52, was arrested in April and imprisoned without trial for an initial three months, under an Israeli procedure known as administrative detention. His lawyers appealed to an Israeli military court, which on Thursday ruled that he should be freed on Sunday. But military prosecutors now want to put him on trial and are asking for him to be kept behind bars in the meantime. "The military prosecution appealed the ruling and filed an indictment, while requesting he be detained until the end of the proceedings," an army statement said. "The military court has currently extended the detention until Monday." Administrative detention allows Israel to hold prisoners without trial for periods of up to six months, renewable indefinitely. About 7,000 Palestinians are in Israeli prisons, more than 10 percent of them in administrative detention. Barghouti, a professor at Al-Quds University, once worked on NASA-funded projects in the United States. He was arrested Sunday night by Israeli security forces at a West Bank checkpoint near the village of Nabi Saleh, west of Ramallah. The professor's family received a phone call from the Israeli military informing them of his arrest, was not told what he was charged with or where he was taken, the Palestinian news site Qudsnet reported. Neither the IDF nor Israel Police would comment on the matter, and it remains unclear which branch of the Israeli security forces was responsible for his arrest. Barghouti earned his doctorate at Utah State University, and joined Al-Quds University in 2000. He was previously detained by the Israeli Border Police while trying to cross into Jordan in December 2014 on unknown charges and set free January 22. — Agencies