Kybartai, Lithuania CNN  — 

Having a neighbor like Russia at the end of the street means 59-year-old Vytas Grudzinskas doesn’t get much rest. “I can see the soldiers best at night,” he says, pointing to a patch of green behind his neighbor’s garden.

“They have a shooting range they use over there behind that field. In the afternoon, you can hear the guns,” he said.

Grudzinskas has his own weapon, a machine gun, which he keeps locked in a cupboard, close at hand – although his guard dog, a Maltese terrier, might be less effective in battle.

The small city of Kybartai where Grudzinska lives lies inside both NATO and the European Union but also along one of the world’s hottest borders – the Suwalki corridor. This tract of land, about 60 miles wide, is sandwiched between Russia’s heavily fortified, nuclear-armed, Baltic bolthole of Kaliningrad and its ally, Belarus. The pass – viewed by many analysts as a weak point within NATO – is caught in a pincer grip between Kremlin troops. The fear is that if Ukraine fell, Russia would advance through it next, possibly cutting off the Baltic states in days.

New members of Lithuania's century-old militia, the Riflemen, are sworn in at a ceremony on Monday.
Kalvarija, Lithuania

The scars of Soviet occupation run deep in this part of Europe. Tens of thousands of Lithuanians were forcibly deported to gulags in Siberia and the far north by the Soviets in the 1940s and 1950s. Almost 30,000 Lithuanian prisoners perished in the forced labor camps.

“My father was sent to Sakhalin in Russia’s far west for 15 years,” said Grudzinskas. “He ate grass the first year to survive.”

So, when Russia annexed Crimea in 2014, Grudzinskas joined Lithuania’s century-old volunteer militia – the Riflemen – and took up arms in his own backyard.

That means he’s the first line of defense if the Kremlin’s troops, stationed 60 feet away in the Russian exclave, put one foot on NATO soil.

“How can you trust Russia? With our history?” he asked.

“Of course, I’m scared. How could I not be?” he added. “My family is here. I built this house with my bare hands.”

Vytas Grudzinskas and a fellow volunteer are seen on a hill in the Suwalki Corridor.

The 103-year-old Riflemen militia has seen its numbers balloon since Russia invaded Ukraine in February, according to its commanding officer.

Currently there are about 12,000 volunteer members, said Egidijus Papeckys, commander of the Riflemen’s 4th R