Russian forces are massing on Ukraine's border. Bluff or not, Putin is playing with fire

A satellite view of the Pogonovo training area in Russia's Voronezh region, close to the Ukrainian border.

London (CNN)For an army given to masking its moves, surely the worst way to disguise a potential imminent invasion of a country is by overtly preparing for it.

This is the paradox around Russia's visible buildup in its west, not far from the Ukrainian border. Were Moscow trying to reverse the military stalemate around the Donbas separatist region -- that it truncated from Ukraine in 2014 -- would it want to telegraph its moves so blatantly?
Russia's signals are obvious. Relentless social media videos show armored convoys moving towards the general border area. These led to open-source intelligence sleuths @CITeam_en spotting a congregation of likely hundreds of vehicles not far from the Russian city of Voronezh. That is still over 100 miles from Ukraine, but it is a sizeable buildup that was captured on satellite images from the Maxar technology group.
    A buildup of vehicles at the  Pogonovo training area, seen in Maxar's satellite image.
    The White House said this week that Russia now has more troops near the Ukraine border than any time since 2014 -- when the peninsula of Crimea was annexed. Further south, military intelligence reports have assessed that some 4,000 heavily armed Russian forces had been seen moving in Crimea, a US defense official told CNN.
      Moscow is also talking the game. Russian defense minister Sergei Shoigu has announced snap readiness inspections for the army. The Kremlin's envoy to the conflict, deputy head of the presidential administration Dmitri Kozak, said that Moscow would, as has pretty much always been implied, come to the defense of Ukraine's eastern population if needed. And he said the start of a conflict would be the "beginning of the end of Ukraine." Russia's declarations are pretty noisy.
      For Ukraine's part, President Volodymyr Zelensky has moved some units closer to the Donbas, and took a very high-profile trip to the area Thursday. Like Russian leader Vladimir Putin, Zelensky's domestic ratings are not that healthy. He talked the language of peace. He tried to be close to the troops, aware that US President Joe Biden has said he will stand by him.
      Ukrainian President Volodymyr Zelensky (right) handshakes with a soldier during his visit to a front in Donbas, Ukraine on April 08.
      The White House has said it is "increasingly concerned by recent escalating Russian aggressions in eastern Ukraine" and US officials have also hinted they might send warships to the Black Sea, a signal of increased involvement, even though American aircraft have regularly been monitoring that area. German Chancellor Angela Merkel asked Putin to pull his forces back during a call on Thursday. Everyone is getting very excitable, very fast.