Israel has ordered its military to stop Greta Thunberg’s aid boat from reaching the Gaza Strip.

Israel Katz, the Israeli defence minister, vowed to “take whatever measures necessary” to stop the vessel docking in the war-ravaged territory.

“You should turn back – because you will not reach Gaza,” Mr Katz said, addressing the 22-year-old climate campaigner directly, and describing her and her companions as “the anti-Semitic Greta and her fellow Hamas propaganda spokespeople”.

He went on: “I have instructed the IDF (Israeli Defence Forces) to act so that the ‘Madeleine’ hate flotilla does not reach the shores of Gaza – and to take any means necessary to that end.

“Israel will act against any attempt to break the blockade or assist terrorist organisations – at sea, in the air and on land.”

Ms Thunberg is one of a dozen activists aboard the Madleen sailboat, which left Sicily last Sunday carrying food and medical supplies with the aim of breaking Israel’s sea blockade of Gaza.

The group of activists said they were hoping to reach Gazan waters as early as today in order to deliver aid to Palestinians.