Russian Deputy FM: US Involvement in Ukrainian Incursion 'a Fact'

Russian Deputy Foreign Minister Sergei Ryabkov said on Tuesday that the involvement of the United States in Ukraine's ongoing incursion into Russia's western Kursk region is "a fact," the TASS state news agency reported.

Ryabkov did not offer evidence to back up that assertion, but he said, without offering details, that Moscow's response may be much tougher than before, another state news agency, RIA, reported.

The White House has said it had no prior knowledge of the Ukrainian operation.