from the WSJ it was Russians or pro-Russian militants who got hold of APCs somewhere
from The Times (London) it was defecting Ukrainian troops joining the pro-Russian side
from a pro-Ukrainian-interim-government source it was Ukrainian troops using Russian flags as cover to infiltrate areas held by pro-Russian militants.
I think we can conclude we haven't a clue what was going on, who the folks in and on the Russian-flag-flying APCs were, or what they were doing beyond riding around in and on APCs flying Russian flags.
One thing we know for sure is that American taxpayers will be sending a big fat check to Putin to pay off Ukraine’s gas arrears to Gazprom very soon courtesy of Obama and Kerry.
“I think we can conclude we haven’t a clue what was going on.”
One of the main principles of modern warfare.
Large flagged armies have gone the way of the redcoats.