Russia's ambassador to Poland has been summoned over statements by a former Russian commissioner for children's rights calling for the killing of the Polish ambassador in Moscow, a Polish foreign ministry spokesman said Friday.

"The Polish side strongly protested this position and expects to immediately start criminal proceedings and punish the perpetrator immediately," ministry spokesman Lukas Gasena wrote on Twitter, referring to Russia's former Commissioner for Children's Rights Pavel Astakhov.

Relations between Russia and Poland have deteriorated further since the war in Ukraine began, especially after Warsaw positioned itself among Kiev's staunchest allies.

Last month, Russian experts revealed in a report published by the Russian website "NewsRe" that Poland is preparing to fight a war against Russia in the coming years, and warned that all scenarios are open if Warsaw takes this step.

The site quoted Polish historian Mikhail Krupa as warning – in an article published in the American magazine "Chronicles" – that the "Americanization" of Warsaw's foreign policy precipitates a war between Russia and Poland.

Krupa added that the Polish authorities intend to fight Russia by any means, explaining that the anti-Moscow sentiment that the Polish authorities have is a source of comfort for the White House.