Morocco is working hard to detain and place on trial citizens who have returned home after fighting for ISIS, the countrys anti-terror chief, Abdelhak Khiam, has told Agence France Presse. "We have arrested and brought to justice more than 200 returnees," Khiam, director of the Central Bureau of Judicial Investigations (BCIJ), said in an interview. He said the suspects were serving sentences ranging from 10 to 15 years in prison. Legislation passed in 2015 allows police to arrest and interrogate returnees before transferring them to the judiciary, he said. In 2015, an estimated 1,600 Moroccans had joined the ranks of militant groups in Iraq and Syria. "Some died in suicide operations or were shot by (international anti-ISIS) coalition forces," Khiam told AFP. "Others fled to other countries." Moroccan authorities regularly announce the dismantlement of "terrorist cells", although such announcements have fallen from 21 in 2015 to nine in 2017. Khiam also praised the role of international cooperation, saying Moroccos security services had prevented attacks in seven European countries. But he admitted there may be "gaps" and urged authorities to inform "countries of origin" in cases where dual citizens are suspected of preparing attacks.