In a letter seen by Euronews, authorities have asked Russians living in the country who they think rightfully owns Crimea, and their views on the Ukraine war.
Lithuania has revoked the residency permits of more than 100 Russians living inside the country, deeming some a security threat.
In figures shared with Euronews on Monday, the country's Migration Department said it had stripped 38 Russians of their permanent residency in 2022, plus a further 97 so far this year.
That's a total of 135 since Russia invaded Ukraine.
Despite increasing restrictions, the number of Russians applying for residency permits in Lithuania doubled between 2021 and 2022 to almost 4,000, according to the Migration Department.
Many are fleeing the rule of Russian President Vladimir Putin and the Ukraine war's fallout.
The right to live in Lithuania can be taken away for several reasons, such as if a foreigner commits a "very serious crime", "poses a threat to state security" or society, the Migration Department said in a statement sent to Euronews.
On Friday, the Lithuanian State Security Department (VSD) announced it had expelled Russian citizen Vladimir Vodo, a self-described "journalist".
"Taking into account the current geopolitical situation", they told Euronews Vodo was a security risk.
He had "disloyal views towards Lithuania, disseminates pro-Russian propaganda in social media and had contacts with Russian and Belarusian intelligence services," they said.
Vodo calls himself a freelance journalist on LinkedIn, having worked for a number of Russian outlets, though Euronews cannot verify the authenticity of this account.
Moscow's invasion of Ukraine last year heightened security concerns in the small Baltic state.
Bordering the Russian enclave of Kaliningrad, the staunch ally of Kyiv was once part of the USSR and now feels threatened by a revisionist Russia.
Officials in Vilnius find themselves in a tricky position. There is a desire to support opponents of Putin and his Belarussian counterpart Alexander Lukashenko, but some in government claim there are also security concerns about allowing citizens of these countries in and out of Lithuania.
Touristic visits to Lithuania by Russians were banned last year, like in many other parts of Europe.
As seen by Euronews, Lithuania's Migration Department has sent surveys to Russian citizens living inside the country, asking them questions about who rightfully owns Crimea and their views towards the war.
Crimea is a Black Sea peninsula that was illegally seized from Ukraine by Russia in 2014, shortly after Ukrainians deposed Moscow-backed president Viktor Yanukovych.
Ownership of Crimea has been contested throughout history, passing from power to power over the centuries.
Some Russians living in Lithuania have complained they face hostility over their government's invasion of Ukraine.
Speaking to Euronews in June, one Russian working in the country said he had suffered abuse and discrimination, despite protesting against the invasion back in his hometown St. Petersburg.
Support for Ukraine is very high in Lithuania. Many Lithuanians are scathing of Russia, scarred by what they call the occupation, exploitation and Russification of their country under the USSR, though there is ambivalence in some quarters.