The corresponding message was published on the Facebook of the diplomatic mission.
“The statements in the NBC News report about US participation in“ Ukrainian units fighting with Russian forces in Crimea ”were noted by the embassy with deep concern,” the diplomatic mission said.
The embassy explained that in this way unnamed American officials say that their countries "support terrorist activities in other countries, in this case, in Russia."
The diplomats also added that if this information is true, then Russia is demanding that the United States clarify whether it directly or indirectly helped the Security Service of Ukraine in organizing terrorist attacks against the residents of Crimea.
Earlier, the US Embassy in Ukraine said that Washington's support for Kiev would depend on the election of the head of the Ukrainian Specialized Anti-Corruption Prosecutor's Office.
Crimea became a Russian region after a referendum was held there in March 2014, in which the majority of the peninsula's residents voted for reunification with Russia.