Activists sailing on dozens of boats attempting to break Israel’s maritime blockade of the Gaza Strip to deliver humanitarian aid say Israeli forces intercepted them overnight Wednesday into Thursday, detaining the crews while the flotilla was sailing hundreds of kilometres from Gaza near the southern Greek island of Crete.

The Global Sumud Flotilla set sail earlier this month from Barcelona. Organisers have said more than 70 boats and 1,000 people from around the world would be participating, with more vessels joining the original boats as the flotilla sailed east across the Mediterranean.

Their attempt comes less than a year after Israeli authorities foiled another effort by the activist group to reach Gaza.

“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,” the group said in a press release. The distance is about 1,000km from Gaza.

Israel’s Foreign Ministry said in a post on X that it was taking about 175 activists from more than 20 boats participating in the flotilla to Israel. According to the ships’ tracker published on the activist group’s website, 22 vessels had been intercepted in international waters west of Crete, and 36 others were still sailing by midmorning Thursday.

Israel and Egypt have imposed varying degrees of a blockade on Gaza since Hamas seized power from rival Palestinian forces in 2007. Israel says the blockade is needed to prevent Hamas from importing arms, while critics say it amounts to collective punishment of Gaza’s Palestinian population.