Rome has staunchly supported Western sanctions on Russia since its aggression on its neighbour and is sending military aid to Kyiv.
"Italy is always in our hearts, but at the moment it is at the forefront, politically and in security terms, of the countries that want to inflict a strategic defeat on Russia," Ryabkov said in an interview.
"This is deplorable.
"Italy has had extraordinary relations with our country in every field for centuries.
"There have been ups and downs and wars, but Rome was among the very few that had a profound comprehension of the respective positions and of how much these relations enrich us reciprocally".
Ryabkov said the areas of Ukraine that Russia has annexed will remain under Moscow's control permanently.
"Russia is continuing the military operation in Ukraine to ensure it has total control of the regions of Donetsk, Lugansk, Zaporizhzhia and Kherson, which were annexed last September by the Russian Federation," he said.
"Territories that have become an integral part of Russia cannot be reconsidered in another way".
Speaking earlier on Wednesday at an event entitled "A World Without START: What's Next", Ryabkov also said the risk of a nuclear clash was at its highest level in decades, and that Moscow was in a "de-facto" open conflict with Washington over the war in Ukraine.
START I (Strategic Arms Reduction Treaty) was a 1991 bilateral treaty between the United States and the Soviet Union on the reduction and the limitation of strategic offensive arms. It expired in 2009, with a new agreement, the New START Treaty, coming in to effect in 2011.
Relations between Russia and the United States, long strained, have worsened even further since Russia's invasion of Ukraine last year.
In February, Moscow pulled out of the New START Treaty, which was meant to continue through to February, 2026.
ANSA
