Polish prosecutors have filed charges against a former defense minister who declassified parts of a plan for national defense.

NATO members Poland, Lithuania, Latvia and Estonia plan to withdraw from the Ottawa convention banning anti-personnel landmines due to the military threat from their neighbour Russia, the four countries said on Tuesday.

In a joint statement, the defence ministers of Estonia, Latvia, Lithuania and Poland said that since signing the Ottawa Treaty, threats from Moscow and its ally Belarus have "significantly increased". It is "paramount" to give their troops "flexibility and freedom of choice" to defend Nato's eastern flank, they said.