ANCIENT ROME (AP) — Defense Secretary John Mattis says allied nations should take responsibility for their citizens who’ve been detained as foreign fighters for that Islamic State group in Syria.

Mattis states “doing nothing is not an option, inch even as some governments have indicated little interest in having such militants returned.

Mattis was speaking carrying out a meeting of defense ministers within Rome that included a discussion as to what to do with the detainees, without fixing the issue.

The U. S. -backed Syrian Democratic Forces are currently keeping thousands of IS detainees, including countless foreign fighters from a number of countries. Last week, they announced they’d taken two notorious British members of the Islamic State cell who were generally dubbed “The Beatles” and had been known for beheading hostages.