Israel’s defence minister has vowed to prevent an aid boat carrying Greta Thunberg and other activists from reaching the Gaza Strip.

Israel Katz said on Sunday that Israel will not allow anyone to break its naval blockade of the Palestinian territory, which he said is aimed at preventing Hamas from importing arms.

He said in a statement: “To the antisemitic Greta and her fellow Hamas propagandists – I will say this clearly: You should turn back, because you will not make it to Gaza.”

Climate campaigner Thunberg is among 12 activists aboard the Madleen, which is operated by the Freedom Flotilla Coalition.

The vessel departed Sicily last Sunday on a mission that aims to break the sea blockade of Gaza and deliver humanitarian aid, while raising awareness over the growing humanitarian crisis in the Palestinian enclave.

The activists had said they planned to reach Gaza’s territorial waters a week later.

Rima Hassan, a French member of the European Parliament who is of Palestinian descent, is among the others onboard. She has been barred from entering Israel because of her opposition to Israeli policies towards the Palestinians.

After a three-month total blockade aimed at pressuring Hamas, Israel started allowing some basic aid into Gaza last month, but humanitarian workers have warned of famine unless the blockade and the war end.

An attempt last month by Freedom Flotilla to reach Gaza by sea failed after another of the group’s vessels was attacked by two drones while sailing in international waters off Malta. The group blamed Israel for the attack, which damaged the front section of the ship.