The Global Sumud Flotilla said Thursday that Israeli forces seized 21 of its boats in international waters a few miles off Greece's territorial waters.
The group said 17 vessels managed to escape and enter Greek waters following the incident.
The Israeli Foreign Ministry claimed in a statement through the US social media platform X that approximately 175 activists from more than 20 boats of the flotilla "are now making their way peacefully to Israel."
Earlier, the Gaza-bound fleet said that Israeli naval forces intercepted and disabled several of its vessels in international waters, leaving hundreds of civilians stranded at sea as a storm approached.
Late Wednesday, the Israeli Army Radio said naval forces had started taking control of flotilla vessels bound for Gaza far from Israel's coast.
It added that Israeli forces had so far seized seven of the flotilla vessels near the Greek island of Crete.
The flotilla, carrying humanitarian aid for Gaza, aims to break Israel's blockade and open a humanitarian corridor by sea.
Israel has imposed a blockade on the Gaza Strip since 2007, leaving about 1.5 million Palestinians out of roughly 2.4 million homeless after their homes were destroyed during the war.
