The first ship taking part in Freedom Flotilla III set sail on Monday as pro-Palestine activists from Sweden and Norway boarded the trawler in Gothenburg, and are heading for the blockaded Gaza Strip.
Israel has already condemned the mission as an unnecessary provocation
The flotilla is the third of its kind since 2010, when the first Freedom Flotilla was attacked by Israel naval forces, who killed ten activists on board the ships.
The incident, which took place in international waters, sparked international outcry.
Gaza has been under a crippling Israeli-administered military blockade since 2007.