Jerusalem - A Palestinian clown accused by Israel of membership in a banned leftist group and held without charge for 20 months has been released.Mohammad Abu Sakha, 26, said on Thursday he was released the day before from administrative detention, the controversial measure under which Israel detains suspects without trial for periods of several months, renewable indefinitely.He said following his release he returned to the northern West Bank city of Jenin, where family and friends were waiting to welcome him."It was like a party," he said.Abu Sakha had been part of the Palestinian Circus School in Bir Zeit in the occupied West Bank since 2008, first as a student and later as a clown and teacher.He said Israeli forces never told him the exact reason for his arrest in December 2015 or how long he would be detained.Israel's Shin Bet security agency accused him of being a member of the leftist Popular Front for the Liberation of Palestine, which the Jewish state considers a terrorist group because of its armed wing.Amnesty International had called for his release.He said he would "absolutely" be returning to the circus as it was "a message"."Israel arrests people every day, and closes them off economically," he said. "The circus gives people hope."The Israeli army did not immediately respond to requests for comment.Administrative detention is intended to allow authorities to hold suspects without charge so information is not disclosed that could jeopardise security.The system has been criticised by Palestinians, human rights groups and members of the international community.Of around 6200 Palestinians currently in Israeli jails, around 450 are being held under administrative detention, Palestinian rights groups say.