"I think that we can find courage and call it genocide because there is so much resemblance of the events of 20th century that we thought belonged in the history books," Lithuania's top diplomat said. "We have to remind ourselves of those events, compare them and find the exact wording for how to call it."
In his words, it's important to bring those responsible to justice.
"But again, I think it's also important not only to call it what it is, but also to find those who are responsible for them and bring them to justice," Landsbergis said, adding that one must be prepared to see more atrocities withdrawing Russian troops left behind.
"The more territories are liberated by the Ukrainian army, the more atrocities we will know of," he said.
This will require not only reactions from politicians but also specific measures the West can take, he added.
The Ukrainian army recaptured Bucha, an important town in the Kyiv region, a few days ago and announced it had found dozens of dead bodies after the Russian withdrawal.
The Kremlin rejects accusations that Russian troops killed civilians near Kyiv and has claimed that the gruesome photos and videos are "fakes" staged by Ukraine.
Ukrainian President Volodymyr Zelensky has called the killings war crimes and genocide, and Western countries are responding with tougher sanctions against Russia.