As much as Russia tries to hide the presence of Russian troops in the eastern Ukraine (Donbas) those troops have become more and more visible to the general public. The rebel controlled areas of Donbas are not heavily policed and many of the civilians there don’t want to be ruled by Russia but keep their mouths shut and their cell phone cameras active. With the addition of commercial satellite photos and military grade satellite photos released by the United States it has been possible to identify the extent of the Russian effort.
Initially Russia used some Spetsnaz commandos in civilian clothes and locally hired mercenaries to organize armed militias in Donbas. This overwhelmed local police and before Ukraine could get large numbers of troops into the area Russia had arranged for groups of Russian volunteers (most of them Russian nationalists, not Russian soldiers told to leave their uniforms behind and head for Donbas) to show up and suddenly the Donbas rebels were expanding the area they controlled. But by June 2014 the Ukraine Army was on the scene in strength and pushing the rebels back.
In response Russia implemented what could be called “Plan B” in July. This involved sending in more Spestnaz to keep the rebels from completely falling apart, along with thousands of Russian combat troops to halt the Ukrainian advance and push them back. Russia brought in more armored vehicles (often repainted to look like captured Ukrainian stuff), many of them more modern vehicles than Ukraine had. These were often not repainted to appear Ukrainian. In addition artillery (guns and rocket launchers) and anti-aircraft missile systems just across the border in Russia were used to fire at Ukrainian forces in Ukraine. The Ukrainian troops did not expect such heavy artillery fire nor the surface-to-air missiles that were suddenly shooting down Ukrainian aircraft. The Ukrainians pulled back and once they halted the Russian advance there was a ceasefire in September. Russia kept violating the ceasefire and in January brought in more troops and advanced again. It was clear from the rebel prisoners and dead bodies that a lot of the “rebel” fighters were actually Russian troops. This could be confirmed on the Internet where Russian language social media was full of Russian conscripts reporting on their adventures in Donbas.
From all this it appears that Russia has brought in over 40,000 combat and support troops from over a hundred different units. These troops are usually brought in for a few months, or as many as six months, then sent back to their home base and replaced by another unit. This is causing problems in Russia because many of the troops involved are conscripts and when these are killed the official story is that they died from something other than combat. The bodies are shipped home in sealed caskets which are often, in violation of government instructions, unsealed. When that happens the parents discover that their son died in combat and that gets around via the Internet and some of the more daring mass media. Most Russian mass media is government controlled, but the Internet dilutes the news monopoly that control of mass media used to confer. The situation has gotten worse as Russia has begun using special units of Interior Ministry Police to work behind units in combat and arrest any troops, usually conscripts, who try to run away. This harkens back to the World War II practice of having groups of KGB men behind the front line with orders to shoot on sight any troops they saw moving away from the fighting.
Russia still pushes the official line that they have no troops in Ukraine and call any evidence to the contrary another example of how clever and insidious the NATO plot against Russia is. So far this is selling well inside Russia but not so much anywhere else.