Amnesty International has called the continued detention of a Palestinian circus trainer by Israel "shameful".
Mohammad Abu Sakha was arrested in December without charge, and has been detained for six months.
According to Israel's Shin Bet security service, Mr Abu Sakha was arrested in the West Bank for "renewed activity" with the Popular Front for the Liberation of Palestine. But Amnesty's Philip Luther said Israel must "either charge him with a genuine criminal offence or order his release".
The 23-year-old is part of the Palestinian Circus School, which trains children and specialises in working with those with special needs.
When Amnesty supporters held a protest outside the Israeli embassy in London in March to raise awareness of his case, the embassy declined to comment.
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