Early Tuesday morning, as John Kerry arrived in Kiev, pro-Russian troops fired warning shots at about 300 unarmed Ukrainian solders outside of the seized Sevastopol, Belbek airbase in Crimea. The confrontation was captured on video and broadcast on Sky News.

In the video, a pro-Russian militia member can be heard telling a Ukrainian leader, "We'll be shooting your legs."

The Ukrainians largely keep their cool, though one soldier reportedly responds, "You will pay for this. You'll be responsible." And another Ukrainian soldier can be heard calling the pro-Russian troops a "bitch."

The pro-Russian troops appear to be taking orders on cellphones, which would confirm—or at least keep up the appearance—that they're members of a pro-Russia militia, as Putin has claimed, and not actual Russian solders.

According to Sky News' Katie Stallard, who witnessed the confrontation, the wives and mothers of some of the Ukrainian troops intervened.

"There are around a dozen women, wives and mothers, standing in front of their men because they believe they (Russian soldiers) will be more reluctant to fire on them," Stallard said.