A Canadian boat of pro-Palestinian activists bound for Gaza was stopped shortly out of a Greek port Monday, while other ships set sail symbolically to show defiance for a Greek ban. Greek coastguards halted the Canadian vessel Tahrir about 10 minutes after it left port on the island of Crete Monday afternoon with some 40 people on board, organisers said. \"They have been boarded by armed coast guards,\" said a spokeswoman for the Canadian Gaza organisation during an Athens press conference. Meanwhile in the port of Piraeus, near Athens, French activists were joined by Americans from the US Audacity of Hope boat, keen to show support after their own attempt to sail had been thwarted Friday by authorities imposing a ban on all Gaza-bound ships leaving Greek ports. \"And we\'re off!\" shouted the passengers, cheering and waving as the captain of the Louise Michele unfurled the sails and wildly beeped the boat\'s horn, chanting \"One, two, three four, Occupation No More!\" Greek coastguard officials moved in swiftly to ask what the activists were carrying on board, but let the demonstration continue. The French Boat to Gaza campaign had renewed their request for permission from authorities to leave the port on Monday morning, but had been told that the ban remained in place. They were carrying a small amount of aid on board. Activists from the impounded Audacity had begun a hunger-strike in front of the US embassy on Sunday to protest against the arrest of their captain, who was allegedly being held in \"shocking conditions\". They were quickly moved on by police. Captain John Klusmer was arrested Friday by authorities after his ship was intercepted in Greek waters. French Captain Alain Connan said he had decided not to set sail because he risked being slapped with a long prison sentence. Head of the Palestinian National Initiative (PNI) Moustafa Barghouti said the demonstration was an \"exciting moment\" and that people in Gaza had \"already called to say how grateful they are for such a devoted show of solidarity\". Standing out on deck wrapped in a Palestinian flag, he said the protest was helping \"expose not only Israel\'s blockade and occupation but also the complicity of the European and American governments\". Frustrated that the flotilla had been thwarted by Greek authorities in its attempt to breach Israel\'s sea blockade, French member of parliament Jean-Paul Lecoq said activists hoped to challenge the ban in European courts. \"This is a time for everybody to act responsibly,\" Greek foreign ministry spokesman Grigoris Delavekouras said at a news briefing. \"We are at a critical juncture in the Middle East, where tension is running high,\" the spokesman said. He warned the activists against \"any development that could lead to a deteriotation of the regional climate or to incontrollable situations that could threaten the lives of those wishing to take part in the operation.\" Passengers in T-shirts reading \"Stay Human\" and \"Do No Harm\" hugged each other on the boat and said that their mission was not over. \"What people have done today will be written with the ink of dignity,\" Barghouti said.