Story highlights Two officials may have been slipped a date-rape drug, according to a report

The US is declining to comment on the specific incident but raising concerns of Russian harassment

Washington (CNN) A top Russian official strongly denied Wednesday a report that Moscow may have been behind the alleged drugging of two US diplomats in St. Petersburg and suggested instead that the pair may simply have been drunk.

"We are outraged," Russian Deputy Foreign Minister Sergey Ryabkov said in a statement posted on the Russian Foreign Ministry website, adding the claim may have been the work of the US State Department seeking "revenge" for the collapse of talks between the two counties to address the situation in Syria.

Russia's denial came after a report two days ago by Radio Free Europe/Radio Liberty that the diplomats -- a man and a woman who were not senior officials -- allegedly had their drinks spiked with a date-rape drug while attending a United Nations convention on corruption last November. The report, attributed to anonymous sources, said the State Department quietly protested the incident to Russian officials.

The story also said one of the diplomats had been treated at a "Western medical clinic" - which Russia said was not true.

"A probe conducted by Russia revealed that at the time no Americans had sought treatment at any St. Petersburg medical institutions," Ryabkov said. "If, alternatively, they had just been boozing at a hotel bar, they have only themselves to blame."

Read More