The sailing boat Madleen – operated by activist group Freedom Flotilla Coalition — departed from the Sicilian port of Catania, in southern Italy.

It will try to reach the shores of the Gaza Strip in an effort to bring in some aid and raise “international awareness” over the ongoing humanitarian crisis, the activists said at a press conference on Sunday, ahead of departure.

“We are doing this because, no matter what odds we are against, we have to keep trying,” Thunberg said, bursting into tears during her speech.

“Because the moment we stop trying is when we lose our humanity. And no matter how dangerous this mission is, it’s not even near as dangerous as the silence of the entire world in the face of the live-streamed genocide,” she added.

Israel, which was founded in the aftermath of the Holocaust, has adamantly rejected genocide allegations against it as an antisemitic “blood libel.”

In mid-May, Israel slightly eased its blockade of Gaza after nearly three months, allowing a limited amount of humanitarian aid into the territory.

Experts have warned that Gaza is at risk of famine if more aid is not brought in.

UN agencies and major aid groups say Israeli restrictions, the breakdown of law and order, and widespread looting make it extremely difficult to deliver aid to Gaza’s roughly two million Palestinians.

Among those joining the crew of the Madleen are Game of Thrones actor Liam Cunningham and Rima Hassan, a French member of the European Parliament who is of Palestinian descent. She has been barred from entering Israel due to her active opposition to the Israeli assault on Gaza.

The activists expect to take seven days to get to their destination, if they are not stopped.

Thunberg, who became an internationally famous climate activist after organising massive teen protests in her native Sweden, had been due to board a previous Freedom Flotilla ship last month.

That attempt to reach Gaza by sea, in early May, failed after another of the group’s vessels, the “Conscience”, was attacked by two alleged drones while sailing in international waters off the coast of Malta.

The group blamed Israel for the attack, which damaged the front section of the ship, in the latest confrontation over efforts to send assistance to the Palestinian territory devastated by nearly 19 months of war.

The Israeli government says the blockade is an attempt to pressure Hamas to release hostages it took during the October 7, 2023, attack that triggered the conflict. Hamas-led militants assaulted southern Israel that day, killing some 1200 people, mostly civilians, and abducting 251. Hamas is still holding 58 hostages, 23 of whom are believed to be alive.

In response, Israel launched an offensive that has killed over 52,000 Palestinians, mostly women and children, according to Gaza’s Health Ministry, which does not distinguish between fighters and civilians. Israel’s bombardment and ground operations have destroyed vast areas of the territory and left most of its population homeless.

The Flotilla group was only the latest among a growing number of critics to accuse Israel of genocidal acts in its war in Gaza. Israel vehemently denies the allegations, saying its war is directed at Hamas militants, not Gaza’s civilians.

“We are breaking the siege of Gaza by sea, but that’s part of a broader strategy of mobilisations that will also attempt to break the siege by land,” said activist Thiago Avila.

Avila cited the upcoming Global March to Gaza – an international initiative also open to doctors, lawyers and media – which is set to leave Egypt and reach the Rafah crossing in mid-June to stage a protest there, asking Israel to stop the Gaza offensive and reopen the border.