Mr Hamdi claims his detention represents a "war against freedom of speech" for both Americans and Britons, linking it to his vocal criticism of Israel's military actions in Gaza.
He described his detention conditions as "sheer agony" in a crowded space with 80 to 90 inmates and said he witnessed "merciless" treatment by ICE officials.
Mr Hamdi said he believes his words are considered a threat by establishment figures due to changing American public opinion against Israel.
A US Department of Homeland Security spokesperson labelled Hamdi an "illegal alien and terrorist sympathiser" and said that under President Donald Trump, those supporting terrorism would not be allowed into the country.