Abdullah Abu Rahma has had several run-ins with the army and has spent time in jail in the past for organising weekly demonstrations against Israel's separation barrier in the village of Bilin.
The activist, who has organised the protests for the past 11 years, was arrested again on Friday, said his brother Rateb Abu Rahma.
He was moved to the Ofer military prison in the West Bank on Saturday and told his lawyer he had been accused of "interfering with the work of the army in a closed military zone," he added.
Over the years foreign and Israeli demonstrators have joined Palestinians staging weekly protests in Bilin.
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Rateb Abu Rahma said that Israeli activists were arrested alongside his brother on Friday. Contacted by AFP, the Israeli army declined to comment.
Israel began building what it calls its "security fence" in 2002 after a wave of Palestinian attacks.
The Palestinians see it as a land grab aimed at stealing part of their future state, referring to it as the "apartheid wall".