Europe’s Eastern Border Is Facing a New Underground Migration Route

The fortified borders between Belarus and the European Union were designed to make mass crossings harder, more visible and more expensive. But a new pattern is beginning to undermine that logic. Instead of climbing fences or cutting through barriers, migrants are increasingly being moved through tunnels dug beneath them.

The discovery of a tunnel in southeastern Latvia on August 11 has brought the issue into sharper focus. Border guards first encountered 15 migrants moving through a forest near the Belarusian frontier. Their clothes were covered in sand, and questioning eventually led officers to a tunnel exit hidden only about 10 metres from Latvia’s border fence. It was the first migrant tunnel discovered on the Latvian side, but not the first such route to emerge along the EU’s eastern frontier.

What is changing is not simply the method of crossing. The tunnel network points to a broader adaptation of the migration pressure that Belarus’s western neighbours have been trying to contain for years.

The border fence has pushed the route underground

The migration crisis on the Belarus-EU frontier reached its peak in 2021, when large numbers of migrants, mainly from the Middle East, attempted to enter Poland, Lithuania and Latvia from Belarus. The response was increasingly physical: fences, surveillance, patrols and restrictions transformed the border into one of the most heavily secured sections of the EU’s external frontier.

That strategy initially worked. But it also created an incentive for smugglers and migrants to search for routes that bypass the infrastructure altogether.

Poland discovered the first known migrant tunnel from Belarus in September 2025. Several more followed, including a passage near Narewka through which around 180 people, mostly Pakistani and Afghan nationals, entered Polish territory in December. Lithuania has recorded 12 attempts to dig tunnels into its territory since the beginning of 2026.

The significance is therefore less about the number of tunnels than about the direction of adaptation. Europe built a barrier above ground. The networks facilitating crossings are now testing whether that barrier can simply be bypassed below it.

Lithuania is already treating tunnelling as a security problem

Lithuanian authorities have repeatedly discovered unfinished underground passages originating from the Belarusian side. Some of the tunnels have been reinforced with wooden supports, suggesting that at least some were designed to withstand continued use rather than serve as improvised holes beneath the border.

In one incident in July, Lithuanian media reported that a border guard was injured after migrants who had emerged from a tunnel attempted to pull him towards Belarusian territory. Lithuanian authorities have also begun looking for technologies capable of detecting underground activity and are cooperating with Polish border officials on methods of identifying tunnelling.

This changes the technological requirements of border security. Cameras, drones, thermal imaging and ground patrols are effective against visible movement. They are considerably less useful when the route itself is concealed underground.

The next generation of border surveillance is therefore likely to involve sensors and other systems designed to detect disturbances beneath the surface. The frontier is becoming not only a line to monitor, but a three-dimensional security environment.

The unanswered question is what happens on the Belarusian side

The most politically sensitive element is not whether tunnels exist. It is whether Belarusian authorities are enabling them.

Lithuania says it has no proof that Belarus is directly involved in constructing the passages. But Lithuanian border officials say they have repeatedly informed their Belarusian counterparts about suspected tunnel locations, including through specific intelligence, only for Minsk to deny that any construction was taking place.

Latvia has gone somewhat further in its assessment. A spokesperson for the Latvian State Border Guard said there were reasonable grounds to suspect that support for the digging was being provided from inside Belarus. The area on the Belarusian side close to the border is restricted, with access limited to authorised border guards.

That distinction matters. The existence of a tunnel does not by itself prove state direction. Smuggling organisations can operate independently, particularly when there is a profitable market for moving people into the EU.

But the geography creates a difficult question for European security services: how much independent criminal activity can occur in a tightly controlled border zone without at least some degree of tolerance, logistical assistance or deliberate non-intervention by the authorities controlling that territory?

Migration is becoming part of a wider hybrid-security environment

Belarus has already demonstrated that migration can be used as a source of political pressure on the EU. During the 2021 crisis, European governments accused Minsk of deliberately facilitating the arrival of migrants and directing them towards the EU’s external borders. Belarus rejected those accusations and has continued to blame Brussels for the confrontation.

Aleksandr Lukashenko has also previously indicated that Belarus would no longer prevent migrants from trying to reach the EU, framing the policy as a response to European sanctions.

The tunnel phenomenon adds another layer to this confrontation.

A conventional migration route is relatively easy for a state to deny responsibility for. A criminal group can be blamed, migrants can be described as acting independently and border incidents can be presented as failures of European controls.

Underground routes create an even more ambiguous environment. They can be organised by smugglers, tolerated by local authorities or deliberately exploited by state actors without leaving the kind of visible evidence associated with a conventional border operation.

That ambiguity is itself strategically useful.

The eastern frontier is becoming harder to police

For Poland, Lithuania and Latvia, the immediate problem is practical. The countries have invested heavily in physical barriers precisely because they wanted to reduce uncontrolled movement across the border. Tunnels challenge the assumption that stronger fences automatically produce stronger borders.

They also force European governments to integrate migration control more closely with intelligence and national-security structures.

A tunnel is not necessarily evidence of a broader hostile operation. But once underground infrastructure begins appearing repeatedly across several countries, security services cannot treat every incident exclusively as an immigration-control problem. They have to consider who is financing the routes, who is providing equipment and expertise, where the migrants are being assembled and whether the infrastructure could eventually be used for purposes other than migration.

This is why Latvia's first tunnel has significance beyond the 15 people intercepted after emerging from it. The episode demonstrates that the tactics used along the Belarusian frontier are adapting faster than the security architecture built to contain them.

Europe's eastern border is no longer simply a wall separating the EU from Belarus. It is becoming a testing ground for increasingly sophisticated forms of irregular movement, smuggling and hybrid pressure.