WARSAW (Reuters) -- Polish President Lech Kaczynski, a frequent critic of the Kremlin, has invited Russian leader Dmitry Medvedev to this month's celebrations marking the 65th anniversary of the liberation of the Nazi death camp Auschwitz.
Up to 1.5 million people, mostly Jews, perished at the camp in southern Poland during World War II before Soviet Red Army troops liberated it on January 27, 1945.
Kaczynski's office confirmed the invitation to President Medvedev in a short statement on his web page.
As part of the celebrations, the museum that now runs the Auschwitz site plans an exhibition in the former prisoners' barracks chronicling the liberation.
The exhibition is part of efforts by Polish Prime Minister Donald Tusk's center-right government to improve ties with Russia, long strained by rows over energy, defense, and history.
Russians are deeply proud of their country's victory over Nazi Germany in 1945 after a titanic struggle in which up to 27 million Soviet citizens perished. Poland lost about a fifth of its own population, or six million people, during the war.
Ties between Russia and NATO member Poland suffered under the previous Polish administration of Jaroslaw Kaczynski, the president's twin brother, which lost power in 2007.
President Kaczynski, a conservative, remains a strong critic of what he sees as Russian efforts to reassert its influence in former Soviet republics such as Ukraine and Georgia.
He also backs possible Polish involvement in U.S. global missile defence plans which Moscow views with scepticism.