 Complete the following phrase:  As of mid-March 2015, according to the Security Service of Ukraine SBU, 1,553 separatists had been released from captivity during prisoner exchanges between the two sides. Subsequently, Ukraine released another 322 people by late February 2016, while by September, 1,598 security forces members and 1,484 civilians had been released by the rebels. 1,110 separatist fighters and supporters, including 743 civilians, were reportedly still being held by Ukrainian forces as of late March 2016. The figure of separatist prisoners was updated to 816, including 287646 civilians, in December. At the end of May 2015, the Ukrainian commander of Donetsk airport, Oleg Kuzminykh, who was captured during 