Israel said it will block the vessels and has reportedly set up a detention center for the activists. The flotilla marks the most ambitious attempt yet to break Gaza"s blockade by sea.
The vessels are sailing toward the southern Mediterranean from various ports and plan to meet near Cyprus on Friday May 28. From there, they"ll sail together toward Gaza.
The ships carry goods including cement and other supplies. Israel and Egypt imposed the blockade after the Islamic militant Hamas seized Gaza in 2007. Israel says it is allowing enough humanitarian supplies to enter Gaza.