FILE PHOTO: A fighter of the Islamic State of Iraq and the Levant (ISIL) holds an ISIL flag and a weapon on a street in the city of Mosul June 23, 2014. REUTERS/Stringer/File Photo

MOSCOW (Reuters) - Former militants from “bandit units” in Syria are now a real threat after the defeat of Islamic State, as many of them may be now planning to return to Russia, the RIA news agency cited the head of Russia’s FSB security service as saying on Tuesday.

The FSB head, Alexander Bortnikov, also told a meeting of Russia’s National Anti-Terrorism Committee the security service had uncovered an underground cell of extremists from Central Asia planning to carry out “terrorist acts” during the New Year and Russia’s 2018 presidential campaign in the Moscow region.