Territorial changes of the Baltic states

In January 1945, some territories of Estonian SSR were ceded to the Russian SFSR: the Russian–Estonian boundary in the north of Lake Peipus was moved westwards by about 12 kilometers from its interwar location (which was delimited by the Treaty of Tartu); the new boundary (which exists up until these days) runs along Narva river. The Russian-Estonian boundary that used to run in the middle of Lake Peipus did not change, while the boundary south of Lake Peipus was also moved westwards (by about 25 kilometers). Overall, about 2000 km² of land changed hands, including Ivangorod (Jaanilinn, then eastern suburb of Narva), the town of Pechory (Petseri), and areas in and around Izborsk (Irboska), Lavry (Laura), and Rotovo (Roodva), and the Kolpina Island (Kulkna) in southern Lake Peipus.

In the late 1944, a territory in northeastern Latvian SSR of about 1,300 square kilometers was ceded to Russian SFSR. This area includes towns of Pytalovo (until 1938 Jaunlatgale, since 1938 – Abrene) and four rural districts. All these areas during the interwar constituted the eastern part of the Abrene County of Latvia. They were added to Pskov Oblast of Russian SFSR. Russian-Latvian boundary in the southeastern Latvia did not change.

After the annexation of Lithuania into the Soviet Union in 1940, a new eastern boundary of Lithuania (Lithuanian SSR) was delimited. The boundary which was delimited in 1920 by Soviet–Lithuanian Peace Treaty had not been the eastern and southern boundary of Lithuania during most of the period because the Vilnius region became part of Poland in early 1920s. Lithuania, however, continued to claim the 1920 border as official and the Soviets continued to recognise these areas as part of Lithuania rather than Poland as well. In 1940, when Lithuania was incorporated into the Soviet Union, a new boundary was drawn, enlarging the de facto Lithuanian territory, though not to the full extent of the republic's claim. The notable gain was the city of Vilnius, which again became Lithuania's capital. The control of the Vilnius region was partitioned between the Lithuanian SSR (including towns of Švenčionys, Druskininkai and the village of Dieveniškės), the Belarusian SSR and Nazi Germany (the latter territory was returned to Poland after World War II). Main cities that were recognised by Soviets as a part of Lithuania by the 1920 treaty but were not added to Lithuanian SSR include Hrodna (Gardinas), Lida (Lyda), Smarhon (Smurgainys), Pastavy (Pastovys), Ašmiany (Ašmena), Brasłaŭ (Breslauja), Suwałki (Suvalkai).

The Estonia-Russia border treaty had been signed in Moscow on 18 May 2005 and ratified by Estonia, but was not ratified by Russia — official reason for this was the fact that Estonia's internal treaty ratification legislation passed by parliament mentioned the 1920 Treaty of Tartu (the treaty under which these territories were originally recognised as Estonian).

On 6 September 2005, the Russian Ministry of Foreign Affairs summoned Anne Härmaste, Chargé d'Affaires ad interim of Estonia in Russia, and handed her a note containing a notice of the intention of the Russian Federation to withdraw its signature and not to become a party to the Treaty Between the Russian Federation and the Republic of Estonia on the Russian-Estonian State Border and to the Treaty Between the Russian Federation and the Republic of Estonia on the Delimitation of the Sea Areas in the Narva Estuary and Gulf of Finland.

The Treaty of Tartu is considered to be a historical document of no legal power by Russia, while in Estonia the situation is different, as officially Estonia considers itself the continuation state of the interwar Estonia.

It was assumed that the Russian-Latvian border treaty would be signed in 2005. In Latvia the opposition, primarily the organization Abrenian Union (consisting of people deported from Pytalovo and surroundings, sometimes referred to as the Association of Abrene Residents), lobbied for nationwide referendum on such treaty as they saw it as violating the constitution of Latvia (principle of territorial unity).[2] The government ruled out a possibility of referendum, however the negotiations for border treaty were suspended by Russia after the Latvian parliament issued a declaration stating that Latvia was occupied by the Soviet Union and claiming material compensation from Russia for the period of occupation.

President Vladimir Putin in his speech regarding these territories said that "it goes against the spirit of modern Europe" to raise issues like this one, that "Russia as well has lost many of its external territories during the breakup of the Soviet Union, such as the Crimea". In an interview with Komsomolskaya Pravda in May 2005, Putin addressed the issue of Pytalovo, when he stated that Russia would not hold any negotiations with Latvia which involved territorial losses for Russia.[3][4]

Lithuania immediately after independence recognised the borders established in 1940 as the borders of Lithuania and signed border agreements with Belarus and Poland. Relations with neighbouring Russia have been strained since then but maintain diplomatic alliance with Poland and Belarus.