A flotilla of boats headed for Gaza carrying 350 pro-Palestinian activists - including climate change campaigner Greta Thunberg - has departed from Barcelona.
Around 20 vessels displaying Palestinian flags left the Spanish port at 19:00 local time on Monday, stocked with medical and food supplies.
The flotilla first attempted to set sail on Sunday but had to return to port due to stormy weather.
The aim of the mission is to break Israel's illegal siege on Gaza, according to the organizers, although a previous attempt to reach Gaza by sea was intercepted by Israeli forces.
The Global Sumud Flotilla Mission plans to launch in two waves - the first from Barcelona and the second from Tunis on 4 September.
Activists hope the boats will converge in the Mediterranean before sailing towards Gaza, a trip estimated to take seven or eight days.
We are sailing again to break the siege and open up a humanitarian corridor, Thunberg stated in a video message.
Punk singer Bob Vylan, who stirred controversy with a chant against the Israel Defence Forces at Glastonbury, spoke at the flotilla's departure, calling the activists brave individuals aiming to do what should have been a governmental intervention long ago.
Israeli authorities have previously labeled such missions as publicity stunts, claiming they do not aid humanitarian efforts.
Following a nearly three-month total blockade on Gaza earlier this year, a UN-backed body declared parts of the territory facing famine.
On previous occasions, boats attempting to deliver aid were intercepted by Israeli forces, with activists escorted to ports and deported.
In June, a yacht carrying Thunberg and activists with limited humanitarian supplies was intercepted as it aimed to reach Gaza.
This mission may evoke memories of the tragic 2010 incident when Israeli commandos opened fire, killing 10 individuals on board the Mavi Marmara, a vessel leading an earlier aid flotilla to Gaza.
