"(Tomasz) Szatkowski is accused of improperly handling classified documents, having contacts with foreign special services, obtaining unauthorized financial benefits," Tusk said in parliament, citing a counterintelligence investigation.

He also accused Szatkowski of "relying on the suggestions and advice of foreign companies to prepare important state documents directly related to state security".

Szatkowski was appointed ambassador to NATO in 2016 by the former populist ruling party, and was recalled to the country in May by the current Foreign Minister Radoslaw Sikorski.

Tusk also accused the former ruling party, including President Andrzej Duda, of having known about the accusations against Szatkowski even before his NATO appointment, and of having hidden them.