The United States has barred a delegation of Russian health officials from talks in Washington this week as the U.S. simmers over the deployment of Russian troops in crisis-stricken Ukraine, RIA Novosti reports.

The U.S. embassy notified the delegation’s head that its invitation was being rescinded less than a day before the group’s planned departure to the U.S. to discuss Kazakhstan’s potential accession to the World Trade Organization, Russian officials said Monday.

Russia’s veterinary and agricultural watchdog, Rosselkhoznadzor, which was sending the delegation, denounced the measure as “sabotage,” according to a statement posted on the agency’s website.

Troops widely believed to be Russian but lacking official insignia have deployed across Crimea since Thursday, isolating Ukrainian military installations and urging soldiers stationed inside to lay down their arms.

U.S. Secretary of State John Kerry said Sunday that the U.S. was prepared to economically isolate Russia, while promising financial support for the new Ukrainian government, made up of an erstwhile opposition that ousted President Viktor Yanukovych, a close ally of Russia, on Feb 22.

Washington earlier said it had abandoned preparations to attend a summit of the Group of Eight powerful democracies to be held in the Russian city of Sochi in June.

On Monday, all members of the bloc besides Russia signed a statement condemning the reported deployment as a violation of Ukraine’s sovereignty and territorial integrity.

The latest round of talks on Kazakhstan’s WTO accession is being held March 3-6 in Washington, and the Rosselkhozdnadzor representatives were to participate as experts.

The agency had recently partially lifted a ban imposed on U.S.-produced meat imports last year due to concerns about a growth stimulant in animal feed.