"We are, as you know, very actively constantly monitoring the aspect of detainees and those who are being abducted [in Syria], but we did get the information today from one main source, but we would like to have more information, that some substantial number of fighters appear to have been released … we are talking about thousands and thousands," de Mistura said during a press conference.
Answering a question on the issue, the UN official said he "learned it from the Russian side… There was something issued by the Sweden side. We have asked… for more information in order to assess if these people are genuine fighters, political prisoners."
Syria has been mired in civil war since 2011, with government forces loyal to Syrian President Bashar Assad fighting against numerous opposition factions and extremist groups.
The issue of releasing of the detainees has been brought up by de Mistura and the West multiple times.
On December 18, the UN Security Council adopted resolution 2254, reaffirming the goals of the previous Vienna deals to bring the entire spectrum of political groups in the crisis-torn country to the negotiating table. The resolution also calls for release of all "arbitrarily detained" persons.
