International nonprofit organisation Freedom Flotilla Coalition (FFC) said one of its vessels left the Italian port of Catania on Sunday, heading for Gaza to deliver humanitarian aid after a previous attempt failed due to a drone attack on a separate ship in the Mediterranean. The crew of volunteers, including climate activist Greta Thunberg and Irish actor Liam Cunningham, set sail on the Madleen, carrying barrels of what the group called "limited amounts, though symbolic", of relief supplies.

"We are doing this because, no matter what odds we are against, we have to keep trying," Thunberg said during a tearful speech. "Because the moment we stop trying is when we lose our humanity. And, no matter how dangerous this mission is, it's not even near as dangerous as the silence of the entire world in the face of the live-streamed genocide."

This voyage marks the FFC's second attempt in as many months to break the blockade.

An earlier mission in early May was aborted after another FFC vessel, the Conscience, came under attack by two suspected drones while navigating international waters off the coast of Malta.

The activists anticipate a seven-day journey to their destination, provided they are not intercepted along the way.