The 22-year-old Swedish activist says she and a group called the Global Sumud Flotilla will be launching “the biggest attempt to break the illegal Israeli siege over Gaza” on August 31, Al Jazeera reports.

Dozens of boats will set sail from Spain on the day and will meet dozens more that will sail from Tunisia and other ports on September 4, she said in a post on Instagram.

“We are also mobilising more than 44 countries on simultaneous demonstrations and actions to break complicity in solidarity with the Palestinian people!” she added.