If the GRU, CIA, MI6 and other covert agencies weren't inside Ukraine I would be amazed. As for the communications intercepts, I don't think the GRU would be that sloppy.
“As for the communications intercepts, I don’t think the GRU would be that sloppy”
The rebels are using CB’s and Ham Radios to communicate with each other.
if FSB/GRU were there, they would be using encrypted equipment that only the NSA could read.