The head Ukraine's Security Service Vasyl Hrytsak has said the location of 57 hostages captured by illegal armed gangs is established.

"For now, we have know where 57 [hostages] are held, if they haven't been transferred to another place," Hrytsak said at a briefing in Kyiv on Friday.

The information was sent to the office of German Chancellor Angela Merkel and French President Francois Hollande, the SBU head said.

The SBU says militants currently hold 111 citizens of Ukraine captive. Nine of them are in the Russian Federation. Some 499 individuals are unaccounted for.