Thirty pro-Palestinian activists on a Canadian boat bound for Gaza that was stopped out of a Greek port Monday for breaking a ban, defied authorities by claiming they had all captained the ship.
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.
"We have been boarded by about 15 armed special forces," David Heap of the Canadian Boat to Gaza organisation told AFP by phone from the vessel.
"I'm being blocked by a man with a machine gun," he said over the noise of shouting from passengers he said were being pushed around. "We are not using force back," he added.
The Tahrir, which was carrying activists from Canada, Belgium, Italy, Switzerland and Turkey, was forced to turn back to Aghios Nikolaos port in Crete, as Heap and others shouted, "We have to go to Gaza. Let us pass!"
It had sailed without a captain in the hope of avoiding a severe legal repercussions.
Passenger Joseph Dube, a former Belgium senator with an expired captain's licence, had sailed the ship and agreed to take full legal responsibility, according to the Tahrir's spokesperson Huwaida Arraf.
When authorities boarded the boat and demanded to speak to the captain, some 30 passengers "claimed they were the captain," she said.
"Everyone took part in manning the boat in one way or another -- they all had a go at sailing it. The idea is that it will be difficult to arrest 30 people," she said.
The Canadian boat was the second in the Freedom flotilla to attempt to set sail. The US Audacity of Hope boat had been thwarted Friday by authorities imposing a ban this week on all Gaza-bound ships leaving Greek ports.
Its American captain John Klusmer was arrested Friday after his ship was intercepted in Greek waters and is due to appear before a prosecutor on Tuesday in the port of Piraeus near Athens.
It is not yet clear what will happen to the passengers on the Tahrir.
"We left as a volunteer crew. It was legal for us to do so under international law, they had no right to stop us," Heap said, adding: "Our destination is still Gaza."
Earlier on Monday, French activists had been joined by their American counterparts to stage a "symbolic departure," on the Louise Michel boat in defiance of the Greek ban.
"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.
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.
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 deterioration of the regional climate or to uncontrollable situations that could threaten the lives of those wishing to take part in the operation."