Washington and Brussels have condemned a planned agreement between Russia and a Moscow-backed breakaway region of Georgia.
EU foreign policy chief Federica Mogherini said the so-called "alliance and integration" treaty between Russia and South Ossetia "clearly violates Georgia’s sovereignty and territorial integrity."
Mogherini's statement on March 17 comes ahead of the expected signing of the treaty by Russian President Vladimir Putin and South Ossetia separatist leader Leonid Tibilov in Moscow on March 18.
Mogherini said the expected signing would be "yet another step" against "ongoing efforts to strengthen security and stability in the region."
U.S. State Department spokeswoman Jen Psaki said Washington did not recognize the planned treaty nor a similar pact Moscow agreed with Abkhazia, another breakaway region of Georgia, last year.
Psaki said Washington continues to support Georgia's independence and territorial integrity.
Russia recognized South Ossetia and Abkhazia as independent nations following Moscow's five-day war against Georgia in 2008, and maintains thousands of troops in the regions.