A U.N. envoy on Friday called on Israel to do all it can for the health of a Palestinian prisoner who has been on hunger strike for the past 55 days in protest of his detention without charge. Robert Serry, the U.N. special coordinator for the Middle East peace process, said he "follows with concern reports about the deteriorating conditions" of Khader Adnan, who has been refusing food since December 18-longer than any Palestinian prisoner before him, according to Palestinian officials. Serry said he "calls on the government of Israel to do everything in its power to preserve the health of the prisoner and resolve this case while abiding by all legal obligations under international law."