The International Committee of the Red Cross (ICRC) appealed on Sunday for information on the whereabouts of three employees abducted in Syria more than five years ago and last known to have been held by Islamic State.

Breaking its silence on the case, the independent aid agency identified the three as Louisa Akavi, a nurse from New Zealand, and Syrian drivers Alaa Rajab and Nabil Bakdounes.

U.S.-backed forces proclaimed the capture of Islamic State's last territory in Syria last month, eliminating its rule over a caliphate which it had proclaimed in Iraq and Syria in 2014.