A second flotilla carrying humanitarian aid to Palestinians in Gaza was due to set sail on Sunday from the Spanish port of Barcelona, aiming to break the Israeli blockade.

About 30 boats are expected to depart under the Global Sumud Flotilla initiative, carrying medical supplies and other aid, with additional vessels planned to join along the route to Gaza.

Global Sumud Flotilla Steering Committee members attend a press conference as humanitarian flotilla prepares to depart for Gaza, from Barcelona, Spain, Sunday.Global Sumud Flotilla Steering Committee members attend a press conference as humanitarian flotilla prepares to depart for Gaza, from Barcelona, Spain, Sunday.Close

Global Sumud Flotilla Steering Committee members attend a press conference as humanitarian flotilla prepares to depart for Gaza, from Barcelona, Spain, Sunday. Credit: Albert Gea/REUTERS

Global Sumud Flotilla Steering Committee members attend a press conference as humanitarian flotilla prepares to depart for Gaza, from Barcelona, Spain, Sunday. Credit: Albert Gea/REUTERS

The same organization attempted a similar voyage last October, when the Israeli military intercepted around 40 vessels and detained more than 450 participants, including Swedish activist Greta Thunberg.

Israel, which controls access to the Gaza Strip, says it allows humanitarian aid into the territory. Palestinian officials and international aid organizations, however, say deliveries remain insufficient despite a cease-fire reached in October that included commitments to expand aid flows.

A banner with a message calling for the New Zealand government to sanction Israel on a boat of a Gaza humanitarian flotilla, in Barcelona, Spain, Saturday.A banner with a message calling for the New Zealand government to sanction Israel on a boat of a Gaza humanitarian flotilla, in Barcelona, Spain, Saturday.Close

A banner with a message calling for the New Zealand government to sanction Israel on a boat of a Gaza humanitarian flotilla, in Barcelona, Spain, Saturday. Credit: Nacho Doce/REUTERS

A banner with a message calling for the New Zealand government to sanction Israel on a boat of a Gaza humanitarian flotilla, in Barcelona, Spain, Saturday. Credit: Nacho Doce/REUTERS

Actor Liam Cunningham, who starred in Game of Thrones and is supporting the flotilla but not taking part, told Reuters: “Every kilogram of aid that is on these ships is a failure because all these people on these ships giving up their time to help their fellow human beings are doing what their governments are legally obliged to do.”

Saif Abukeshak, a Palestinian activist and member of the flotilla’s organizing committee, said the mission aims to “open a humanitarian corridor so the aid delivery organisations can arrive.”

Boats of a humanitarian flotilla preparing to depart for Gaza, in Barcelona, Spain, Saturday.Boats of a humanitarian flotilla preparing to depart for Gaza, in Barcelona, Spain, Saturday.Close

Boats of a humanitarian flotilla preparing to depart for Gaza, in Barcelona, Spain, Saturday. Credit: Nacho Doce/REUTERS

Boats of a humanitarian flotilla preparing to depart for Gaza, in Barcelona, Spain, Saturday. Credit: Nacho Doce/REUTERS

The World Health Organization has said that even during armed conflicts, states are obligated under international humanitarian law to ensure access to medical care.

Swiss and Spanish activists involved in last year’s flotilla said they were subjected to inhumane conditions during their detention by Israeli forces, allegations denied by an Israeli Foreign Ministry spokesperson.