Pabrade, Lithuania - North of the Mediterranean and Balkan routes to Europe, some migrants and refugees have discovered an unknown route into the European Union through Lithuania's eastern borders. Despite Lithuanian border guards' efforts, criminal organisations continue to smuggle migrants from Belarus into Europe.

Lithuania - the Baltic nation of three million people - is situated between Russian exclave Kaliningrad, Belarus, Poland and Latvia, making it a geographically convenient gateway to Western Europe.

"The transit route through Lithuania has been used for many years," says Renatas Pozela, commander of the Lithuanian State Border Guard Service. "We are also seeing constant attempts to open new corridors [to Europe], mostly by Syrian and Iraqi refugees who are trying to reach Scandinavian countries."

The new phenomenon in recent years has seen hundreds of Vietnamese migrants attempting to cross into the European Union. This was exacerbated by the economic crisis in Russia, according to Pozela, where most of these Vietnamese had previously worked. Their Chechen smugglers are alleged to have links with organised crime and Russia's Federal Security Service (FSB).

According to national security assessment published in June 2016 by Lithuania's State Security Department, "FSB seeks to recruit persons who organise smuggling activities and transportation of smuggled goods."

Although border authorities in all three Baltic states have been able to arrest low-level members of smuggling rings, "the leaders of these criminal organisations are from [the] Russian Federation", Pozela told Al Jazeera. "For various reasons, they're unreachable by our justice system."

Inside the migrant registration centre in the eastern Lithuanian town of Pabrade, Vietnamese migrants live separated from other detainees and their Chechen smugglers.

"We are trying to prevent prison rules being brought into the centre, as well as limit conflicts arising from cultural differences," says Aleksandras Kislovas - head of the centre.

Nearby, a separate block houses asylum seekers, mostly from the Middle East and Afghanistan. While their applications are being considered, asylum seekers are free to leave the centre for up to 72 hours.

Laying out a stack of black-and-white photographs, Kislovas shows the first inhabitants in the centre, which was refurbished and converted from a Soviet military base in the early 1990s.

"Humanity has been migrating since the beginning of time," Kislovas says. "It will not stop trying to find the best place in the world."

Additional reporting by Jonathan Brown @Jonathaneebrown