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.”