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

About 30 boats planned to leave the Mediterranean port city laden with medical aid and other supplies on the Global Sumud Flotilla, and more vessels are expected to join along the route towards Palestine.

The Israeli military halted the roughly 40 boats assembled by the same organisation last October as they attempted to reach blockaded Gaza, arresting Swedish activist Greta Thunberg and more than 450 other participants.

MISSION TO 'OPEN HUMANITARIAN CORRIDOR'

Israel, which controls all access to the Gaza Strip, denies withholding supplies for its more than 2 million residents. Yet Palestinians and international aid bodies say supplies reaching the territory are still insufficient, despite a ceasefire reached in October which included guarantees of increased aid.

Liam Cunningham, an actor who starred in the Game of Thrones television series who 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."

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

“This is a mission that aims to open a humanitarian corridor so the aid delivery organisations can arrive,” Saif Abukeshak, a Palestinian activist and member of the flotilla’s organising committee, told Reuters.

Swiss and Spanish activists on last year's flotilla said they were subjected to inhumane conditions during their detention by Israeli forces - an allegation that was rejected by an Israeli foreign ministry spokesperson.

-Reporting by Graham Keeley; Additional reporting by Silvio Castellanos, Horaci Garcia, Nacho Doce, Albert Gea, Michele Spatari and Amy McConaghy; Editing by David Holmes/Reuters