Washington (CNN) -- The U.S. State Department on Friday ramped up its warnings urging  Americans not to join other activists in a flotilla, expected to sail  soon, aimed at  challenging Israel's maritime  blockage of the Gaza  strip. According to  organizers, the flotilla is meant  to commemorate the  one-year anniversary of a similar flotilla that  resulted in a clash in  international waters with Israeli  navy  commandos that left nine people  -- including an American citizen --  dead. Secretary of State Hillary Clinton told reporters  Friday that she didn't think the plan "is useful or productive or  helpful to the people of Gaza."
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50 people plan to sail to Gaza to protest Israel's blockage of the Palestinian area
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Last year, 9 were killed after Israeli forces confronted a similar flotilla
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Sec. of State Clinton calls the plan not "useful," urges Americans not to take part
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An activist say the U.S. is giving Israel the "green light" to attack the flotilla
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@placeholder called the report "as biased and as one-sided as the body that has produced it."
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Activists say the blockade is illegal and has worked to undermine @placeholder's  already fledgling economy.
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Clinton  added Thursday that it would be unwise to move toward @placeholder waters  and create "a situation in which the  Israelis have the right to defend  themselves."
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Clinton  added Thursday that it would be unwise to move toward Israeli waters  and create "a situation in which the  @placeholder have the right to defend  themselves."