As the night train from Moscow pulled into Vilnius central station for its scheduled 10-minute stop, a curious pair of eyes peeked through one of its windows – only to disappear behind a hastily closed curtain.

Photograph: Petras Malūkas/AFP/Getty ImagesThe passengers on the train were heading to the Russian exclave of Kaliningrad, which can be accessed via rail only by crossing through Lithuania, and on the platform outside they were faced with images of war and destruction.

Twenty-four large photographs, graphically depicting bombed-out Ukrainian cities, dead Ukrainian children and bloodied Ukrainian bodies with shrapnel wounds, have been installed here by Lithuania’s rail provider LTG, which also provides the locomotive that pulls the Russian carriages through EU territory.

They all carry the same message in Russian, which is repeated through the public address system as the train stops: “Today, Putin is killing civilians in Ukraine. Do you support this?”

“People in Russia don’t have much access to unbiased information,” said Mantas Dubauskas, an LTG spokesperson. “Maybe we can change the minds of just a couple of passengers.”

The installation at Vilnius central station is symbolic of a Baltic nation that doesn’t so much look cowed by the war in a fellow former Soviet state, as emboldened to tell the world it needs finally to stand up to Russia.

A poster of the damaged caused by Russia’s invasion of Ukraine at Vilnius central station. The PA system asks Russians on their way to Kaliningrad if they support Putin’s actions. Photograph: Andrius Sytas/ReutersIn the first few days after Russian troops stepped on to Ukrainian soil on 24 February, anxiety spread around Lithuania, which has been an independent republic since 1990 and a member of Nato since 2004.

“It brought up a lot of historic fears in my country,” said Linas Kojala, director of the Eastern Europe Studies Centre thinktank. “I had dozens of messages from friends asking what would happen next. Some asked if they should leave the country, maybe to Spain or Portugal. You just have to look at a map of the region to feel uncomfortable.”

The southernmost of the three Baltic EU countries, Lithuania borders Kaliningrad to its west and Belarus to its east – a military corridor between the exclave and the client state would cut the Baltic states off from the rest of Europe.

But within days of the start of Russia’s invasion, anxiety in the Baltics had transformed into resolve. In the centre of Vilnius, Ukrainian flags outnumber Lithuanian ones, with the yellow and blue draped around government buildings, sprayed on old city walls or wrapped as scarves around shopfront mannequins.

On 1 April Lithuania became the first EU country to announce that it had abandoned Russian gas, instead meeting its energy demands via a floating LNG terminal in the port town of Klaipėda.

It was also one of the first EU countries to downgrade its diplomatic ties with the Kremlin after reports of war crimes emerged from Bucha, withdrawing its own top diplomat from Moscow and asking the Russian ambassador to leave the Lithuanian capital.

The message was visually underlined by an art performance just a stone’s thrown from the Russian Federation’s diplomatic base in Vilnius: last Wednesday morning, Lithuanian Olympic champion Rūta Meilutytė took a swim in a nearby pond that had been coloured blood-red with natural dye.

“We wanted to remind people how important it is to keep looking at what Russian aggression is doing,” said Berta Tilmantaite, a journalist and artist who helped organise the protest. “I can understand why people look away or get tired of the news.

“But in Lithuania we know Russia, and we don’t feel scared at this moment,” Tilmantaite told the Observer. “We feel a lot of determination.”