Vehicles drive past the embassy of the U.S. in Moscow
Vehicles drive past the embassy of the U.S. in Moscow, Russia August 21, 2017. Reuters

Russia has demanded that the U.S. embassy in Moscow stop spreading what Moscow regards as fake news regarding its military operation in Ukraine and has threatened to expel U.S. diplomats, the TASS news agency reported on Tuesday.

The warning included a harsh message to Lynne Tracy, the new U.S. ambassador to Moscow, TASS said, citing a senior Russian foreign ministry source who said Tracy had been told she must strictly adhere to Russian law when making any statements about Russia's armed forces in Ukraine.

U.S. diplomats engaged in what Moscow called "subversive activities" would be expelled, TASS quoted the source as saying.

There was no immediate comment from the U.S. embassy in Moscow.

Russia has made "discrediting" its armed forces a crime punishable by up to five years in jail, while a charge of knowingly distributing "false information" about the military carries a maximum sentence of 15 years.

Tracy arrived in Moscow last month. Feb. 24 will mark the first anniversary of President Vladimir Putin's decision to send tens of thousands of troops into Ukraine in what he calls a "special military operation".

Ukraine and its Western allies accuse Putin of launching an unprovoked colonial-style war of aggression and reject his assertion that the operation is designed to protect Russia's own security from NATO's eastern enlargement.

'INAPPROPRIATE'

TASS said the official note, which accused the U.S. embassy of interfering in Russia's internal affairs, had been delivered on Tuesday and had accused U.S. diplomats of making what it called "inappropriate" statements about the Russian leadership.

It did not specify which statements it had in mind.

Tracy was heckled by a crowd of people chanting anti-U.S. slogans late last month as she entered the Russian foreign ministry in Moscow to present her diplomatic credentials.

Deputy Foreign Minister Sergei Ryabkov was cited at the time as telling Tracy he expected her to follow the principle of not interfering in Russia's internal affairs.

The U.S. Embassy said at the time: "Ambassador Tracy is focused on maintaining dialogue between our capitals at a time of unprecedented tension, protecting the interests of U.S. citizens detained in Russia, and supporting ties between the American and Russian peoples."

Bilateral relations are near all-time lows.

The United States is Ukraine's biggest Western backer and has supplied it with modern weaponry - soon to include main battle tanks - and imposed a swathe of new economic sanctions on Russia, all in concert with Western allies.