We don’t know what’s going to happen in eastern Ukraine, where for five months government forces have battled Russian-backed separatists while Russian troops, having already seized Crimea, mass on the border.

But there’s some frightening evidence that Moscow intends to invade mainland Ukraine.

“The probability of invasion is much, much higher than it has ever been,” James Miller, managing editor of The Interpreter, told War is Boring in an e-mail. The Interpreter translates media from the Russian press and blogosphere into English for use by analysts and policymakers.

The Russians reportedly have moved military vehicles with “peacekeeping” insignia to the border—a first since the crisis in the Ukraine began. Earlier this month, NATO warned that the Russians could mount an incursion into Ukrainian territory under the guise of a peacekeeping mission.

The Interpreter reports that it has found several pictures and a video showing Russian armored vehicles bearing the insignia “MC,” an abbreviation of the Russian words mirotvorcheskiye sily or “peacekeeping force.”

The video mysteriously disappeared from Youtube on or before Aug. 8, but the Interpreter managed to grab at least one screenshot, below.

Screenshot via The Interpreter

Tweets accompanying the photos claim the vehicles are moving toward the border with Ukraine or are already nearby.

The insignia on the vehicles are similar to markings used by the Russians engaged in “peacekeeping operations” in Transnistria, a pro-Russian breakaway region between Moldova and the Ukraine.

Furthermore, a larger contingent of troops and vehicles is forming behind this reported mobilization—the possible main invasion force. If Russia does attack, it will enjoy a military advantage over Ukraine. Some of Kiev’s troops can be seen in the above photo by the AP’s Evgeniy Maloletka.

Putin is under pressure to act, Miller added, and time is not on his side. “Russia is already engaged in what could only be described as a ‘drip-drip’ invasion already, but the Ukrainian military continues to recapture territory from the separatists,” Miller said.

“If Putin does not invade soon,” he added, “the separatist movement, which was largely manufactured by the Kremlin anyway, may ultimately have been crushed.”

Paul Huard is an educator, analyst and historian who writes about the military, foreign policy and U.S. political history. Sign up for a daily War is Boring email update here. Subscribe to WIB’s RSS feed here and follow the main page here.