Polish Defense Minister Antoni Macierewicz has accused European Council President Donald Tusk of committing diplomatic treason when he was Poland's prime minister -- alleging that Tusk worked with Russian President Vladimir Putin to harm Polish interests after the 2010 plane crash near Smolensk, Russia, that killed President Lech Kaczynski and 95 other people.
The ministry notified the military department of the National Prosecutor's Office on March 21 that it suspected Tusk, who was prime minister at the time, of an "abuse of trust in foreign relations."
The allegations are the latest and most serious move in an internal political row between Poland's ruling right-wing Law and Justice (PiS) party and Tusk, who is a member of Poland's opposition Civic Platform (PO).
Poland was isolated and rebuffed at a European Union summit earlier in March when Tusk, a centrist, was reappointed as European Council president over Warsaw's objections.
The National Prosecutor's Office in Warsaw confirmed it received the ministry's notification.
It now has 30 days to decide whether to investigate.
Tusk dismissed the accusations as "purely about emotions and obsessions."