A flotilla carrying activists and humanitarian aid for Gaza has left Barcelona's port for a second time after the vessels were forced to return a day earlier because of bad weather conditions.

A flotilla of ships has set sail from Barcelona to the Gaza Strip with humanitarian aid and activists on board.

Organizers say climate campaigner Greta Thunberg and other 11 activists set sail on Sunday afternoon for Gaza on a ship aimed at “breaking Israel’s siege” of the devastated territory.