Swedish climate activist Greta Thunberg boarded a Gaza-bound flotilla Saturday in the Tunisian port of Bizerte, joining a multinational convoy organizers say will try to deliver humanitarian supplies to the Palestinian territory and challenge Israel’s naval blockade.

Organizers of the Global Sumud Flotilla said the convoy includes more than 40 vessels and as many as 700 activists from about 40 countries, according to Turkey’s state-run Anadolu news agency. Thunberg, 22, told reporters aboard the flotilla she was “absolutely disgusted and appalled to live in a world where our people in power, everyday, are betraying Palestinians,” and said the risks of the voyage “pale in comparison to what Palestinians face daily.”

Flotilla organizers have billed the mission as a humanitarian maritime convoy and said it would “break Israel’s blockade.” Israeli officials have long criticized such efforts, saying independent sea deliveries are not necessary and can be used for publicity rather than to help ordinary Palestinians. Israel’s Foreign Ministry previously said, “There are ways to deliver aid to the Gaza Strip — they do not involve Instagram selfies.”

Organizers said some flotilla vessels were recently struck by suspected drone attacks off Tunisia’s coast. Tunisian authorities rejected that account, saying there was “no basis in truth” and suggesting fires aboard ships likely started on board. The differing accounts have not been independently verified.

The current voyage follows earlier attempts that were disrupted. Two weeks ago the flotilla set off from Barcelona but was forced back within hours by storms that produced winds of roughly 35 mph. In June, Israeli naval forces intercepted a flotilla vessel carrying Thunberg, seized the boat and deported the activist after detaining participants; Israel later described that interception as a “selfie yacht” cruise.

Israel maintains the naval and land blockade on the Gaza Strip as a measure to prevent Hamas from smuggling weapons into the territory. The restriction was tightened after the Oct. 7 attack by Hamas that killed about 1,200 Israelis and left more than 250 people taken hostage, according to Israeli authorities. Israeli officials have repeatedly said the blockade is essential to national security and to preventing further attacks.

Boat part of Global Sumud flotilla

Organizers describe the convoy as the largest humanitarian maritime effort of its kind and have vowed to press ahead despite the earlier setbacks and Israel’s warnings. The flotilla’s stated aim is to deliver aid directly to Gaza and to draw attention to the humanitarian conditions in the enclave, where infrastructure and supplies remain under strain.

Several of the flotilla’s participants come from Europe and the Middle East; organizers said activists represent a range of civil society groups. International responses to such missions have varied, with some governments urging that aid be delivered through established land crossings and humanitarian channels to ensure safe and effective distribution.

Greta Thunberg walking the waterfront in Bizerte

The situation at sea is likely to remain tense. Israel’s navy has intercepted prior flotillas and says it will act to prevent breaches of its blockade; flotilla organizers say they intend to continue their campaign of maritime pressure in support of Palestinian civilians. Tunisian officials and the flotilla’s backers provided contrasting statements about alleged attacks on vessels, and independent verification of those incidents has not been reported.

The Global Sumud Flotilla’s progress and any interactions at sea will be closely watched by governments, humanitarian organizations and activists on both sides of the dispute, with potential implications for aid delivery, diplomatic relations and the security environment in the eastern Mediterranean.