It said the activists would return to their home countries and the aid would be sent to Gaza through established channels. It circulated footage of what appeared to be Israeli military personnel handing out sandwiches and water to the activists, who were wearing orange life vests.
Lt. Col. Nadav Shoshani, an Israeli military spokesperson, said the ship was still en route to Israel around midday Monday. It was expected to dock at the port of Ashdod.
Thunberg, a climate campaigner, was among 12 activists aboard the Madleen, which set sail from Sicily a week ago. Along the way, it had stopped on Thursday to rescue four migrants who had jumped overboard to avoid being detained by the Libyan coast guard.