Greek authorities have arrested the captain of a boat that is part of a Gaza-bound flotilla trying to deliver humanitarian aid to the Palestinian territory.

It comes a day after a Canadian-organized ship carrying protesters bound for Gaza was prevented from leaving a port near Athens. Greek coast guards boarded the Tahrir on Friday and attempted to arrest Canadian Sandra Rush, a member of the group Canadian Boat to Gaza, for refusing to surrender the boat's registration papers.

On Saturday, authorities arrested the 60-year-old captain of the Audacity of Hope, John Klusmire. He was being held at police headquarters in Piraeus, Greece's largest port city, and will remain there until a court hearing Tuesday. The boat managed to make it out to sea on Friday night before being intercepted by the Greek coast guard.

Coast guard officials said Klusmire faces charges of trying to leave port without permission and of endangering the lives of the boat's passengers. The latter charge is a felony.

Palestinian legislator and former presidential candidate Mustafa Barghouti said the Israeli government pressured Greece.

"Nobody should allow the Israeli government to outsource the siege on Gaza by making other governments do the job that Israel wants to do," he said. 

The Audacity of Hope was carrying 36 passengers, four crew and about 10 members of the media. It was one of nine vessels slated to take part in a flotilla to challenge Israel's sea blockade of the Gaza Strip and deliver aid.

Activists accuse Israel of sabotaging two of those ships, one docked in Turkey and another in Greece. Israel denies the allegations, with Foreign Ministry spokesman Yigal Palmor dismissing the sabotage charges as "ridiculous," calling them "sad conspiracy theories."

Israel says it imposed the blockade in 2007 to stop weapons reaching the militant and political group Hamas, which rules Gaza. Critics describe the blockade as a form of incarceration for Palestinians.

Nine activists were killed last year in an Israeli raid on a similar flotilla.

With files from CBC News