In the week, Aleksandr is an IT programmer, and Konstantin freelances in online advertising.

But on Saturday (January 29), the two met others in an abandoned construction site on the outskirts of Kyiv to train as Ukrainian army reservists - ready to be called up in the event of war breaking out with neighboring Russia.

Nervous over the threat of some 120,000 Russian troops massed near the border with Ukraine, Kyiv has launched a new Territorial Defence force this year.

It wants to build this up into a corps of some 130,000 people.

They may stand little chance against the much bigger and better-equipped professional Russian army.

But the group could be tasked with protecting civilian sites in Kyiv amid any conflict.

Konstantin had avoided any contact with the military after serving a year in the eastern Donbass region in 2014 during Ukraine's general mobilization.

Now though, he wants to be prepared.

"It doesn't really fit to my life. I didn't really want this. After the demobilization, I avoided everything related to war. I guess I have had a big enough break from it, but now the situation is such that it's needed."

Around 70 locals came to train on Saturday.

Some in full infantry gear with hunting rifles and combat experience from when Russia annexed Crimea in 2014.

Others in sneakers and casual sportswear were handed mock wooden rifles.

Aleksandr said he wants to join up before it's too late.

"I'm in my mid-30s and it's time for me to join. And then... I understand that a lot of people have grown up faster (than me), like, they are 18, they can participate and defend our country. But for me, this is the time."

The United States has warned that a military intervention is likely and imminent.

And the West has threatened Russia with heavy economic sanctions should it invade Ukraine again.

Moscow insists it does not want a war, but it has also dismissed calls to withdraw its troops, saying it can deploy them as it sees fit on its own territory.

It has cited the Western response as evidence that it is the target, not the instigator, of aggression.