Thirty-nine boats were due to leave the Mediterranean port city, a spokesperson for the flotilla said, and more vessels also laden with medical aid and other supplies are expected to join along the route towards Palestine.
Rough seas mean the flotilla will sail to another port then head out to international waters later in the week, Thiago Avila, a member of the flotilla’s organising committee, said.
The Israeli military halted a previous flotilla assembled by the same organisation last October as the boats attempted to reach blockaded Gaza, arresting Swedish activist Greta Thunberg and more than 450 other participants.