Together with the ethnic Russians, the Soviet government settled many people from other parts of the Soviet Union in cities like Vilnius and Klaipėda. These are Belarussians, Ukrainians, Armenians, Azeri, Moldovans, people from the Central Asia.
Neither of these ethnicities (with the exception of Belarussians) existed in Lithuania prior to 1940 in numbers larger than 50 individuals. People from all them share certain similar traits. Despite different origins, they are quite frequently using the Russian language at home and they likely speak Russian better than Lithuanian. Due to this reason, they are often grouped together with Russians under the term "Russophone".
Politically the "Russophones" typically identify the Soviet Union positively and are more likely to be atheists than most other ethnicities.
The above traits are more pronounced in some ethnicities (Ukrainians, Belarussians, interethnic Russophone families) and are less pronounced in some others (Georgians for instance). 55% of the Belarusian community speak Russian natively (only 35% speaks Belarusian). The same is true for 66% Jews, 56% Ukrainians, 47% Tatars, 38% Estonians, 36% Armenians, 36% Georgians, 31% Moldovans and 27% Azeris.
The Russophone community was partly created by the Soviet policies which did not establish any non-Russian Soviet language schools, theaters or media outside of that language's titular homeland, forcing the increasing internal migrants (and some historical minorities) to use the wide network of Russian institutions instead.
Due to a wide knowledge of the Russian language in Lithuania people of the former Soviet Union (especially Belarus, Ukraine, Georgia) continue to immigrate, albeit in lower numbers than in 1940s-1980s. This was especially prevalent before the economic downtime of 2008 when they used to take construction, truck driving, and other similar jobs. New immigrants are often less Russified, some of them are actually anti-Russian. Despite immigration, the "Russophone" share decreases with assimilation into Lithuanian and Russian communities: only ~5% of Lithuania's Belarusians and Ukrainians are younger than 19.
Around 2% of Lithuania’s population are from one of these ethnicities (excluding the ethnic Russians).