U.S. Sen. Lindsey Graham (R-S.C.) on Monday responded to reports that Swedish climate activist Greta Thunberg is aboard a vessel attempting to break Israel’s naval blockade of Gaza by tweeting: “Hope Greta and her friends can swim.”

Thunberg and her pro-Hamas cohorts departed from the southern Italian port of Catania on Sunday to “break Israel’s illegal siege of Gaza,” the Hamas-linked Freedom Flotilla Coalition (FFC) announced.

The vessel, Madleen, is carrying a “symbolic” amount of humanitarian aid, according to news agencies. 

Before departing, the group released a statement in which it accused the world of being silent “in the face of the lives being genocized [sic].”

Israel strongly rejects the use of the term “genocide” and defends its naval blockade of Gaza, in place since 2007, as a necessary measure to prevent Hamas from acquiring materials for its terrorist infrastructure.

The latest voyage comes in the wake of another endeavor to break Israel’s naval blockade, an FFC flotilla that left Tunisia earlier this year.

The FCC claimed that the Conscience was hit twice by drones 17 nautical miles (19.5 miles) east of Malta overnight on May 1, “causing a fire and a substantial breach in the hull.” The ship had been waiting to take on board approximately 30 anti-Israel protesters before setting sail to the Gaza Strip.

Israel was immediately blamed for the attack, but Jerusalem has made no public comment about the incident.   

The Freedom Flotilla Coalition includes several Turkish NGOs, among them the IHH Humanitarian Relief Foundation and the Mavi Marmara Association, responsible for the 2010 Mavi Marmara incident, in which nine activists were killed after they attacked Israeli naval commandos.