This article comes from here: http://www.delfi.lt/news/daily/lithuania/article.php?id=17113068. I'm only going to translate the first half of the article.
Great Deportation of 1948 Marked in Lithuania
It has been 60 years since 22 May 1948, the day the Soviet Union began the operation called Vesna. It was the most massive deportation of Lithuanian people in the history of the country. Forty thousand people [11,000 of which were children] were deported from Lithuania. This deportation is remarkable not only for its size, but also because it took place only in Lithuania, Lithuanian Radio reports. Deportations on a massive scale did not affect the other two Baltic States that year. In the entire Soviet Union, about 80,000 people, half of them Lithuanians, were forced to move in 1948.
The largest portion of the deportees at that time were wealthy farmers, who had been called the enemies of collectivization. Historian Arvydas Anusauskas says that the goal of the mass deportation was to crush armed resistance and the boycott of social, economic and agricultural reforms. Other aims were to frighten the remaining population and to furnish laborers for the far eastern and northern parts of the Soviet Union.
The 60-year old plans and maps of the deportation are still stored in top secret archives in Moscow. The first mass deportation took place in Lithuania in 1941.
Events to mark the 60th anniversary of this event are being held in Vilnius and Kaunas.
See also: http://en.wikipedia.org/wiki/Population_transfer_in_the_Soviet_Union