Greek port authorities stopped the Swedish vessel "Juliano" from leaving the Port of Athens and setting sail to Gaza Tuesday evening.
Over the past several days, the Greek Coast Guard has prevented two other ships from sailing to Gaza.
The "Juliano's" passengers, who include Greek, Swedish and Norwegian pro-Palestinian activists, were planning to set sail to Gaza last week, but were stalled over what they claimed was sabotage orchestrated by Israel.
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Israeli expat Dror Feiler told Ynet that the ship "was cleared to set sail this afternoon, but shortly afterwards the Greeks changed their mind.
"We tried sailing anyway, but there are navy ships waiting for us and a ship with media representatives covering the story. I guess who ever is in charge was given orders from high up. We're waiting to see what happens next," he said.
Athens has made it clear it would not allow any flotilla ship to set sail from its ports. Greek Naval Commandos have so far stopped two ships – an American one and a Canadian one – from setting sail to Gaza.
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