- [Narrator] This tiny strip of land in Eastern Europe

is being called NATO's danger spot.

It's known as the Suwalki Gap.

It forms a border between NATO members,

Poland and Lithuania,

and lies in between two Russian military strongholds.

Military strategists say,

"This sparsely populated area

with hills, forests, and small villages

will be a prime target

if Russia decides to attack NATO territory."

Poland and Lithuania are worried about

this scenario becoming reality

as fighters from the Wagner Mercenary Group

arrive on their doorstep in Belarus.

So here's what's at stake

if the Suwalki Gap comes under attack.

The Suwalki Gap is around 60 miles long

and separates Poland to the west

and Lithuania to the east,

to its northwest, lies Kaliningrad

a chunk of Russian territory

with a number of military bases.

It's also home to Russia's Baltic Naval Fleet

and its only ports on the Baltic Sea

that doesn't freeze up in the winter,

but it's not linked to the Russian mainland.

The most direct route from Kaliningrad to Russia

will be through the Suwalki Gap

via Russia's neighbor and ally Belarus,

but the Russian President's Alexander Lukashenko

allowed Moscow to use his country as a base

to launch the full-scale invasion of Ukraine.

Military analysts say,

Russia could attack from two ends of the Suwalki Gap

with soldiers from Kaliningrad

and forces advancing through Belarus,

which would leave NATO members,

Lithuania, Latvia, and Estonia isolated.

Moscow would also gain more access to the Baltic Sea,

a crucial gateway for commercial shipping.

NATO has fewer options to defend its Baltic members by land,

they'll have to send in reinforcements

through Poland to Lithuania by crossing the Suwalki Gap

only two highways and a train line

connect Poland and the Baltic States.

That means this narrow strip of land

could become congested with troops and military hardware.

The stakes were raised even higher in recent months.

First, fighters from the Wagner Mercenary Group

started relocating to Belarus

after aborting a mutiny in Russia in June.

Then, according to Belarusian television,

"Wagner troops began training Belarusian soldiers,

just three miles from the Polish border."

Poland's Prime Minister says,

"The situation is becoming dangerous."

(speaking in foreign language)

- [Narrator] Warsaw responded by sending

up to 10,000 extra troops

to guard its border with Belarus.

Poland and Lithuania have also closed

some of their border crossings with their eastern neighbor.

NATO has tried to strengthen its defenses in the region.

- We're set and ready.

- [Narrator] Multinational battle groups

with around 1,000 troops have been set up

in each of the Baltic States.

(artillery blasting)

Large-scale drills have taken place

in the area close to the Suwalki Gap

as a way to show NATO's readiness.

(helicopter blades whirling)

The Baltic States and Poland

have also ramped up defense spending.

They have all vowed

to spend 3% of their GDP per year on defense,

more than NATO's 2% target.

The leaders of Lithuania, Latvia, and Estonia

want NATO forces to be stationed in the region permanently.

In the meantime,

NATO's defense capabilities in the area strengthened

with two new members, Finland and Sweden.

This opens up a gateway to reach the Baltics by sea and air

boosting any potential defense on land.

Finland and Sweden's militaries

also add hundreds of warplanes, tanks,

and tens of thousands of soldiers to the alliance.

(gunfire blasting)

Analysts say, "This makes a Russian invasion

even more costly."

Finland and Sweden's integration,

means Kaliningrad is effectively encircled by NATO.

Any attack by Russia could leave the Exclave vulnerable

to isolation and blockade by the alliance.

Analysts believe Russia

is unlikely to launch an armed attack on the Suwalki Gap

while he has his hands full with Ukraine.

(crowd cheering)

Polish opposition leader, Donald Tusk,

who's campaigning to become the next prime minister,

accused the governments,

"Of using the Wagner threats

to stoke fear ahead of October's election."

But Poland's governments denies this.

Still, NATO's Eastern members say,

"Wagner's presence on their doorstep

remains a security risk.

That's why they want to make sure the Suwalki Gap

is well defended

to deter any potential aggression from Russia."

(dramatic music)