The boats in the so-called Global Sumud Flotilla want to "break the illegal siege" of the Gaza Strip by opening a humanitarian corridor by sea.
It should not be up to us, says Thunberg before departure, according to several media outlets.
It is the responsibility of countries, our governments and elected officials, to act to uphold international law, prevent war crimes and genocide. It is their legal duty, and they are failing.
Mixture of boats
Thousands gathered at the port of Barcelona to express their support before departure, reports AP. The fleet consists of a wide variety of boats, from dilapidated yachts to smaller sailboats in wood and a number of more industrial vessels, writes the news agency.
This is Thunberg's second attempt to reach the Gaza Strip. In June, she and other activists were stopped by Israel on international waters west of Gaza, taken into Israeli custody and later sent home.
It is unclear how Israel will react this time. According to unconfirmed reports from the Israeli newspaper Israel Hayom, the country's ultra-nationalist security minister Itamar Ben-Gvir will propose to Prime Minister Benjamin Netanyahu during a meeting on Sunday that the activists be detained under strict conditions intended for terrorists.
From over 40 countries
Global Sumud Flotilla describes itself as an independent group without ties to any specific country or political party. Several more vessels will join the sailing while it moves east in the Mediterranean. According to their own statement, they will constitute "the largest solidarity action" in history.
On board are humanitarian aid and activists, volunteers and politicians from over 40 different countries, writes EFE. Just from Genoa, over 300 tons of emergency aid are being sent, according to the news agency.
In addition to Swedish Greta Thunberg and Lorena Delgado Varas, who was recently expelled from the Left Party after allegations of anti-Semitism, the flotilla includes, among others, Barcelona's former mayor Ada Colau and the Portuguese member of parliament Mariana Mortágua.
Arrival in the Gaza Strip is expected in mid-September.
