YEVPATORIYA, Crimea - Along the base's low-slung cement wall, gloved Ukrainian soldiers unspooled wheels of barbed wire, running strands through eyelets banged into the wall and pickets hammered into the ground, creating a zig-zagging web of wire.
It's the latest effort by the command of the 55th Anti-Aircraft Artillery Regiment in the Crimean town of Yevpatoriya to dissuade the pro-Russian forces that have seized Crimea from coming over the wall to capture the base.
The strategy goes like this: If they try to climb over, they'll get ensnared in the barbed wire, allowing the Ukrainian forces to pick them off from behind sandbags a short distance away. But the base's deputy commander quietly admits that the new defenses would do little to slow well-trained Russian soldiers, as the mysterious men outside the front gate are believed to be.
Across Crimea, unidentified troops believed to be Russian have seized Ukrainian military bases with little or no resistance. Several bases have so far refused to surrender, but nor are they showing any willingness to fight if pushed to.
At Yevpatoriya, a solitary Russian truck is parked out front with a handful of armed, camouflaged "green men," as Dr. Sergei Medinsky, a base medic, has taken to calling them.
"They are there, we are here and we've lived with this about a week," he said as he stood guard at the base's command headquarters. "Everyone is afraid of this but it's normal to be afraid, but I think everything will be fine."
He, along many others in Crimea, laugh about the efforts of the troops outside to pretend that they're not Russian.
They have "good equipment and weapons. And they say that they can buy that in any market. I don't understand it, who believes them?"
Upstairs in his office, the base's commander, Col. Andrey Matvienko, is not in a joking mood. He has been given an ultimatum of sorts, a demand from the green men to hand over his base and weapons to the Russian Black Sea Fleet.
"How can I leave this base if there is technical equipment and weapons and I'm responsible in front of the law for it?" he asked. "Our unit has sworn an oath. So this is the situation."
For Matvienko, it's not just about the chain-of-command or pride. The weapons and equipment housed on this anti-aircraft base are not your standard fare: around 200 rockets, 16 tons of TNT and 500 tons of rocket fuel.
"I'm not scared of anything but at present I'm afraid for the citizens of Yevpatoriya," Matvienko said.
If the Russian forces use their weapons and "if this is detonated, the town of Yevpatoriya will be wiped off the face of the earth."
Then, the phone rings. Matvienko's face drains, growing serious and worried. On the line is the new prime minister of Crimea who wants to see the region join Russia after a referendum Sunday.
"We all swore an oath and at present my command is Ukrainian," the commander tells Prime Minister Sergei Aksyonov. "The ones who can give me orders to surrender weapons, to take them out … resolve this with them.
"I guarantee you personally that if you don't interfere, we will not leave the perimeter of the base," he adds.
After hanging up the phone, Matvienko explains: "I agreed so there is no storming of this base. They will not touch the base until the [referendum on the] 16th of March. I will not be touched by the Russian Black Sea Fleet. I don't know if they'll keep their word. I can only give my word."