(CNN) -- Four crew members escaped and two others were taken hostage from the crash of a Ukrainian transport plane hit by a rocket over the Luhansk region near the Russian border, a Ukrainian Defense Ministry spokesman Vladislav Seleznyov said Tuesday.
All eight on board the plane downed Monday were Ukrainians, Seleznyov said. In addition, two others remain missing, he said. It's unclear who is responsible for taking hostages.
The four who escaped "are in a safe location," the Defense Ministry said.
Video posted to YouTube appears to show people watching as at least one person parachutes and a huge plume of dark smoke rises from the ground.
The rocket that struck the plane Monday appears to have come from Russia, Kiev officials said.
The Ukrainian military has been battling pro-Russian separatists in the area where the Antonov-26 aircraft went down, officials said.
The plane's altitude was too high to be fired on from the ground with a portable missile system, according to a statement from Ukrainian President Petro Poroshenko.
The plane was hit with "a more powerful missile weapon that was probably used from the territory of the Russian Federation," the statement said.
A spokeswoman with the Russian President's office said Monday she could not confirm any missile had been fired from the Russian Federation.
On Friday, pro-Russian separatists fired rockets at a Ukrainian military camp in the Luhansk region, killing 19 troops and injuring at least 55 others, according to Ukraine's counterterrorism office.
CNN's Elwyn Lopez contributed to this report.