Several Gaza activists from Germany deported by Israel to Turkey were injured, a Foreign Office spokesman in Berlin said on Friday.
Diplomats only learned this after the activists had landed in Istanbul on Thursday evening, the spokesman said.
He repeated the German government's criticism of what it called a "humiliating treatment" of the detainees by Israel. "From our point of view, this is simply an unspeakable behaviour," the spokesman said.
Israel stopped the Gaza aid flotilla of more than 50 boats earlier this week in international waters near Cyprus. Around 430 activists wanted to break the naval blockade of the Gaza Strip, which is also supported by Egypt. Israel's Foreign Ministry denounced it as "PR campaign in the service of Hamas."
The German Foreign Office said humane treatment of its own nationals was an "absolute priority," the spokesman said. "That includes, above all, physical integrity. In this context, we of course also expect clarification because some of the allegations in the air are serious," he said.
A video shared by Israeli National Security Minister Itamar Ben-Gvir showing the Gaza activists after their arrest sparked international outrage.
The footage shows the minister walking among bound activists with a group of supporters, waving an Israeli flag while mocking and taunting the detainees.
