Israeli forces have intercepted and detained the crews of at least 22 boats near the Greek island of Crete from a flotilla that is attempting to break Israel’s maritime blockade of the Gaza Strip to deliver humanitarian aid.

The Global Sumud Flotilla, consisting of about 58 vessels carrying people from across 70 countries, departed from Italy on Sunday.

Flotilla organisers said in a press release: “Israel’s actions … mark a dangerous and unprecedented escalation, the abduction of civilians in the middle of the Mediterranean, over 600 miles from Gaza, in full view of the world.”

Israel’s foreign ministry said the IDF had taken control of more than 20 boats with about 175 activists onboard. According to a live tracker on the flotilla’s website, 22 boats have been intercepted so far, while 36 vessels are still sailing.

In footage released by flotilla organisers, an Israeli navy officer is heard urging the activists to alter their course. The officer said: “If you wish to deliver humanitarian aid to Gaza, you may do so through established and recognised channels. Please change course and return to the port of origin. If you are carrying humanitarian aid, you are invited to proceed to the port of Ashdod.”

The Global Sumud Flotilla responded in a statement on social media: “Same script, different year. The Israeli navy thinks a radio warning can drown out the cries for justice.”

The flotilla described the interception as a “violent raid in international waters”. In a social media post, the group said that “after smashing engines and destroying navigation arrays, the military retreated – intentionally leaving hundreds of civilians stranded on powerless, broken vessels directly in the path of a massive approaching storm”.

It also said the vessels’ communications had been jammed, hindering them from signalling for help. Asked by Agence France-Presse about the accusations, the Israeli military declined to comment.

Helene Coron, a spokesperson for Global Sumud France, told an online news conference that the operation had taken place at an “unprecedented” distance from Israel, and that those intercepted included a Paris Communist municipal councillor, Raphaelle Primet, and another 10 French nationals.

Israel’s defence minister, Israel Katz, said on Wednesday he had imposed sanctions on the flotilla, which he said had been “organised by the Hamas terror organisation, in cooperation with additional international organisations”.

Turkey’s foreign ministry condemned the interception in international waters as “an act of piracy”. It said: “By targeting the Global Sumud Flotilla, whose mission is to draw attention to the humanitarian catastrophe faced by the innocent people of Gaza, Israel has also violated humanitarian principles and international law.”

Francesca Albanese, the UN special rapporteur for the West Bank and Gaza, said: “How on earth is possible that Israel is allowed to assault and seize vessels in international waters just off Greece/Europe?”

Italy’s premier Giorgia Meloni on Thursday called for the immediate release of Italian nationals onboard the flotilla. Her government “condemns the seizure of the Global Sumud Flotilla vessels … and calls on Israel to immediately release all the unlawfully detained Italians”, Meloni’s office said in a statement.

Israeli authorities had initially said those detained would be taken to Israel, but foreign minister Gideon Saar later wrote on X that the activists would be transferred to Greece in coordination with Greek authorities.

“All participants in the provocative flotilla who were taken off the vessels were taken off unharmed,” Saar wrote on X.

Last October, Israel intercepted about 40 boats from the Global Sumud Flotilla, arresting more than 450 activists, including Greta Thunberg and the French MEP Rima Hassan.

Swedish officials said Thunberg had been held in harsh conditions and witnesses said she was forced to wear an Israeli flag while IDF members were taking pictures of her. Israel subsequently deported those detained.

The Gaza Strip, governed by Hamas, has been under an Israeli blockade – described by the UN as “a direct contravention of international human rights and humanitarian law” – since 2007. The war in Gaza triggered by the Palestinian movement’s attack on Israel has led to severe shortages of food, water, medicine and fuel, and the death of more than 72,500 Palestinians, according to aid agencies.