Poland plans to bring charges against two Russian air traffic controllers over a plane crash in 2010 that killed 96 people, including then-Polish President Lech Kaczynski.
Polish Prosecutor Ireneusz Szelag said the controllers were involved in communicating with the plane as it tried to land in bad weather at an airport near the Russian city of Smolensk. Szelag did not name the controllers or provide details of the charges.
Poland has been one of Russia's harshest critics over its interference in Ukraine, and Russia would be highly unlikely to extradite the controllers to hear the charges.
In addition to Kaczynski, the plane was carrying a number of high-ranking Polish officials.
They were traveling to Russia to commemorate victims of the World War II massacre of Polish military officers at Katyn by members of the Soviet secret police.
Based on reporting by AP and Reuters