Angela Godfrey-Goldstein said that Prof. Jeff Halper, the only Israeli citizen to participate in the protest, was detained by police after he passed through the Erez crossing for violating the law prohibiting Jewish citizens from entering Gaza.
However, Halper was conditionally released later Tuesday. Sderot Police Chief Shimon Nachmani said that "Halper was held for questioning and the decision whether to arrest him will be taken at the end of the probe."
Earlier, Police Spokesman Micky Rosenfeld confirmed that Halper was taken to a police station in southern Israel.
Minnesota-born Halper, an Anthropology lecturer from Ben Gurion University who also chairs the Israeli Committee against House Demolitions, was among dozens of international activists who sailed into Gaza on Saturday to protest the blockade. The others are to sail for Cyprus Thursday.
After considering their response to the sailing protest, Israeli officials finally announced they would allow the boats to dock. Foreign Ministry official Aryeh Mekel said Israel allowed the boats to enter Gaza in order to "prevent a media-covered provocation at sea."
Shmulik Hadad contributed to the story