Right now Russia is moving troops, armor, and advanced antiaircraft missiles toward the border with Ukraine. In the last 48 hours, dozens of videos have been uploaded to social-media sites that show Russian armor very close to the border, many of them confirmed to be within mere kilometers of Ukraine.

On Thursday, my team at The Interpreter definitively geolocated Russian armor only 2,000 meters (and closing) from the border and a Buk, the same type of missile that likely took down Malaysia Airlines Flight 17, only a few hours from being within range of Ukraine’s air force. Columns of tanks, marked with the same painted numbers and flat, pale-green paint we’ve seen in Ukraine since (at least) June 20th, were spotted moving en masse toward a key border crossing. Some Ukrainian journalists are reporting that at least some of this armor has already crossed the border.

Russia’s helicopters held ground-fire exercises Friday on the border between Russia’s Rostov region and Ukraine’s Donetsk region. The head of Russia’s airborne units, which played a critical role in the conquering of Crimea, has pledged to expand operations beyond the boundaries of Russia (tanks marked with the insignia of Russian Airborne forces were captured by Ukrainian troops just yesterday). The Ukrainian government now says that its military has detected even more advanced antiaircraft batteries lined up on its border.

There is now significant evidence that Russia is openly supporting the separatists militarily and many experts now believe that Russia could invade and beat back the Ukrainian anti-terror operation.

An open war between Ukraine and Russia may have already begun. In the last 24 hours, there are reports of cross-border shelling in new locations and 17 new Grad rocket batteries digging in on the Russian side of the border, but within range of the Ukrainian military’s front lines. This is even more concerning when it is put into context. In the last two days, two different Ukrainian military convoys have been destroyed by Grad rockets south of the MH17 crash site, in Shakhtyorsk and near Torez. Russian paratroopers have even taken pictures with the bodies of the Ukrainian soldiers and have posted them to social networks (this isn’t the only time Russian soldiers have posted pictures from inside Ukraine, which has caused the Russian government to discuss banning their soldiers from posting to social media).

Miller points to reports in social media of large numbers of armor either already in Ukraine or very close to the border. But the big question is does Russia really need to invade?

This is troubling for the near term:

Is this just saber rattling? It’s possible. Russia has been poised to invade Ukraine on multiple occasions and it has not happened yet. But in the weeks before and after the downing of MH17, thousands of “tourists” driving tanks and armored vehicles that appear to be from Russian military stockpiles have crossed the border and joined the fight against the fledgling Ukrainian government. Even if Russia does not formally invade, how much of this equipment will not-so-quietly slip across the border and reinforce an insurgency which has already cost so many civilian lives?