The European Union's counter-terrorism coordinator says the Islamic State group still has about 2,500 fighters from Europe among its dwindling ranks.

Gilles de Kerchove told German daily Welt in an interview published Tuesday that the extremist group used to have about 5,000 European fighters in Iraq and Syria.

De Kerchove says about 1,500 fighters have since returned home and 1,000 have been killed. He says many of those remaining are likely to die fighting or at the hands of IS if they desert, while some may move to other conflict areas such as Somalia or Yemen.

According to official U.S. estimates, IS has up to 13,000 fighters overall left in Syria and Iraq.

De Kerchove says the loss of territory won't end the terror threat posed by IS.