Italy informed that it found more secret documents at the spy's apartment and it is feared he sold them to Kremlin.

Italian police have found a stash of classified and highly classified military documents they believe an Italian navy captain gave to a Russian official in return for cash, a judicial source said on Friday.

Walter Biot, 54, was arrested on Tuesday in a Rome carpark. A police source said he had been seen handing information to a Russian military attache in exchange for 5,000 euros ($5,900).

The judicial source with access to the case files said police had recovered a memory card containing 181 photos classified as confidential, nine classified as highly confidential and 47 classified as secret documents from NATO.

The transfer of classified documentation is a hostile act of extreme gravity, commented Foreign Minister Di Maio in a communication with the Senate. Therefore, he added, "we immediately took the necessary measures".

An author of the editorial in the biggest Italian newspaper La Repubblica stated, it was a very serious episode, which showed how Russian is targeting Italy with a new offensive strategy.

In addition to the activities of influence denounced in recent years, like the disinformation campaigns launched on anonymous social profiles and the news spread by organisations close to the Kremlin to delegitimize the Italian government, now there is the accusation of an openly hostile action, such as espionage, the editorial said.

After a long investigation conducted by the Carabinieri del Ros with the collaboration of Aisi, internal intelligence, and the Defense Ministry, the Italian authorities arrested two spies.

Mr. Biot is being held in a Rome jail and has been denied house arrest. He faces a minimum 15 years in prison if found guilty of military espionage.

As usual in the case of high profile Russian spy his lawyer and family tried to portray him as a provider for impoverished family. But the facts indicated a different picture.