Climate activist Greta Thunberg has joined a flotilla of humanitarian aid boats that departed from Barcelona on Sunday, aiming to challenge Israel’s long-standing naval blockade of Gaza. The mission seeks to deliver life-saving supplies to the besieged enclave and draw global attention to what organizers describe as a humanitarian catastrophe.

Thousands of demonstrators gathered at the port to support the departure, waving Palestinian flags and chanting slogans such as “Free Palestine” and “It’s not a war, it’s a genocide.” Addressing the crowd, Thunberg condemned what she called an “extremely violent, business-as-usual international system” that, in her words, is complicit in ignoring violations of international law.

This is not Thunberg’s first involvement in such an effort. In June, she participated in a similar maritime mission, which was intercepted by Israeli forces. The vessel was seized and its passengers deported. Israel defends the blockade, enforced since 2007, as a security measure to prevent weapons from reaching Hamas. It has dismissed these flotillas as political provocations rather than genuine aid efforts.

The latest mission, organized by an international coalition of activists, has sharply criticized global leaders for failing to pressure Israel into easing the blockade. Yasemin Acar, a member of the flotilla’s steering committee, said additional vessels are expected to join from Greece, Italy, and Tunisia. In Genoa, local communities have collected roughly 250 metric tons of food, a portion of which is already on its way to Gaza via Sicily.

The departure comes amid dire warnings from humanitarian agencies about the situation in Gaza. A global food insecurity monitor has declared famine in parts of the territory, where basic necessities remain scarce. According to Gaza’s health authorities, more than 63,000 people—predominantly civilians—have been killed since Israel launched its military campaign in response to the October 7, 2023 Hamas-led attack, which left over 1,200 Israelis dead and 251 taken hostage.

Organizers of the flotilla say their goal is not only to deliver aid but also to spotlight what they term the collective punishment of Gaza’s civilian population through Israel’s blockade and continued military actions.