VILNIUS, Lithuania (AP) — Flowers were laid on rusty railway tracks Monday as Lithuania marked the start of a mass deportation 80 years ago by the Soviet Union that was occupying the Baltic nation.

People who were considered opposed to Moscow or deemed counter-revolutionary elements were sent to Siberia from Lithuania and few returned. Others who owned land or houses were evicted and sent there too.

Some 280,000 people were eventually deported to the Siberian gulags, a year after Soviet troops had occupied Lithuania. Many of those sent away never returned from the long journey in the cattle wagons.

“Two evil forces — Nazi Germany and the Soviet Communist regime — had entered a secret agreement to divide Europe,” President Gitanas Nauseda said during a solemn ceremony in Vilnius, on a day considered one of the darkest pages in the Baltic nation’s recent history. These “regimes caused unspeakable pain and suffering.”

One of those attending the ceremony Monday was deported and spent almost 11 years in Siberia. Aurelija Staponkute and her family were deported only because they had a small farm that was seized.

“We do not know what the future might bring. Whatever happens, we must protect our freedom. After all, we fought for it so hard,” the 83-year-old said.

Only one-third of those deported ever returned, according to historians, and the mass deportation affected all walks of life in the Baltic nation, where it's considered a genocide by an occupying power.

The Soviet occupation of Lithuania lasted for five decades. After regaining its independence in 1991, Lithuania joined the European Union and NATO in 2004.