WASHINGTON, Jan. 21 (Xinhua) -- The U.S. military began transferring up to 7,000 Islamic State (IS) detainees from northeastern Syria to "secure detention facilities" in Iraq, U.S. Central Command (CENTCOM) said Wednesday.

As many as 150 IS fighters held at a detention facility in Hasakah, Syria, were moved "to a secure location in Iraq" as the mission was launched, CENTCOM said in an article on X.

"Facilitating the orderly and secure transfer of ISIS detainees is critical to preventing a breakout that would pose a direct threat to the United States and regional security," CENTCOM commander Brad Cooper said in the article.

Over the past year, U.S. and partner forces have captured over 300 IS members across Syria and killed more than 20 others, CENTCOM added.

Adrian Shtuni, an associate fellow with the International Centre for Counter-Terrorism think tank, said that as of 2025, 21 years after the founding of IS, its territorial presence in Iraq and Syria had diminished significantly.

At its height, IS fielded up to 80,000 militants, including more than 42,000 foreign terrorist fighters from over 120 countries. In contrast, by mid-2025, estimates suggest only 1,500 to 3,000 fighters remain active in Syria and Iraq, said the researcher, noting its threat persists globally. ■