Israel vowed on Sunday to stop an aid boat carrying Greta Thunberg and other activists on board from reaching Gaza.

Israel's foreign ministry has denounced the Gaza-bound ships, including one carrying Greta Thunberg, as a publicity stunt rather than genuine humanitarian aid. The ministry insists that the maritime zone off Gaza is legally blockaded and that aid is already being delivered through official channels.

Climate activist Greta Thunberg has hit back at South Carolina Senator Lindsey Graham for mocking her Gaza trip, saying it spoke "a lot about their priorities".

As the activist set sail on an aid ship bound for Gaza, the senator posted online: "Hope Greta and her friends can swim!"