The embassy's press office said via Facebook that the report's claim that Russia and the US are now negotiating the future of the New START agreement "causes confusion."
"We are not aware of such contacts. It should be noted that a year ago in Helsinki the President of the Russian Federation Vladimir Putin suggested Donald Trump consider the possibility of extending the Treaty after 2021. We have not received any reply yet," the Facebook statement said.
The embassy also complained that the Washington Post report, which dealt with statements by a senior US Defence Intelligence Agency (DIA) official on Russia's alleged "violation" of the Comprehensive Nuclear-Test-Ban Treaty (CTBT), failed to accurately report the facts of the matter.
"Regretfully, the article is another example of amateurishness of American journalism. In pursuit of sensation, the author does not attempt to look into the essence of the problem," the statement said.
"The reason for misleading The Washington Post readers is not clear," it added.
The embassy highlighted other evidence of bias in the Washington Post article, noting that the Russian position was never taken into account.
"If The Washington Post was really interested in clarifying the Russian position and publishing an objective article (rather than another piece of 'fake news' based on extremely controversial assumptions), it should have had a look at Ambassador Antonov’s comment and the statement by the Russian Foreign Ministry on the issue," it added.
The Russian Embassy also responded to the claims made by the DIA official, Director Lt. Gen. Robert Ashley, who said during remarks at a think tank in Washington on Wednesday that the United States believes Russia may not be adhering to the nuclear testing moratorium outlined in the 1996 CTBT accord.
"We will let the claims that Russia may be conducting nuclear tests remain on the conscience of the DIA leadership: the Agency has not provided any facts," the embassy said.
The embassy also reiterated Russia's own concerns about Washington's adherence to New START.
"We emphasize that statements like 'you must believe that we are honouring our commitments' are not credible evidence. Especially if they come from the country discredited by baseless allegations," the embassy said.
New START went into force in 2011 and covers a 10-year period with the possibility of a five-year extension. The agreement limits the number of deployed intercontinental ballistic missiles, submarine-launched ballistic missiles, nuclear armed bombers and nuclear warheads.