Ayman al-Alul, a 44-year-old journalist with the Arab Now news agency, was detained by security services in the Hamas-run Gaza Strip on January 3 and released on Monday.
Alul, whose arrest had drawn protests from journalists and rights groups, said he was detained for comments made on his Facebook page where he has more than 30,000 followers.
"My journalism was annoying them so they charged me with incitement against the government of Gaza and therefore the Hamas movement and the Palestinian resistance," he told AFP at his home in Gaza on Wednesday
Alul said he was exposed to "torture", referring to "verbal abuse that should not be used against a person my age. I am a civilian without any security problems."
He added that while he was hit lightly, the psychological attacks were more damaging.
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For Alul, the goal of his arrest was "to remove criticism of the government in Gaza."
He said he was also arrested two years ago, being held for six days. "This time it was for nine days, and I was slapped a lot."
He added he was determined to keep posting on Facebook but might not criticise the government as much.
"My activities will continue, even if a little less sharply so as not to hurt Hamas or the government."
Dozens of journalists and lawyers last week demanded Hamas release Alul and staged a march in solidarity with him.
Hamas has ruled Gaza since 2007, with Israel imposing a crippling blockade on the enclave.