Authorities in Greece say they have arrested the captain of an American boat that was to be part of the Gaza flotilla.

The 60-year-old captain, whose name was not released by authorities, is being held at Piraeus police headquarters and will remain there until a court hearing Tuesday.

Greece's coast guard said Saturday the captain of the "Audacity of Hope" 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.

The "Audacity of Hope" was due to carry 36 passengers, four crew and about 10 members of the media. Its attempt to sail Friday night from the port of Perama, near Athens, was thwarted by coast guard speedboats.

Israel on Saturday denied claims it sabotaged ships that were part of the planned flotilla.

Activists have accused Israel of damaging two ships docked in Turkey and Greece.

Foreign Ministry spokesman Yigal Palmor dismissed the sabotage charges as "ridiculous," calling them "sad conspiracy theories."

The Turkish daily Hurriyet reported on Saturday that an investigation by Turkish police into the alleged sabotaging of an Irish ship set to take part in the flotilla revealed that the damage to the ship occurred before it docked in Turkey.

Flotilla organizers have claimed that the ship was docked in Turkey’s territorial waters when the alleged tampering occurred.

Hurriyet reported Turkish diplomats as saying that the investigation revealed that the damage done to the ship had occurred before it docked, and was most likely not caused intentionally.