"We have received a letter from Senator John McCain with a request for a financial donation to his presidential election campaign. In this respect we have to reiterate that neither Russia's permanent mission to the UN nor the Russian government or its officials finance political activities in foreign countries," the statement said.
According to Ruslan Bakhtin, press secretary of the Russian mission, the letter dated September 29 and signed by McCain, was addressed to Vitaly Churkin, Russia's envoy to the UN, and arrived on October 16.
The ambassador's title was not included in the letter, and was not clear why the letter had taken over two weeks to arrive.
Enclosed was a request for a donation of up to $5,000 to McCain's election campaign to be returned with a check or permission to withdraw the money from the donor's credit card until October 24.
Individual donations to candidates' election campaigns are capped by law at $2,300, and it is illegal to accept donations from foreign nationals.
McCain accepted the $84 million in public financing available to his election campaign, and consequently cannot accept private donations. However, the Republican National Committee is collecting donations that can be used to support his candidacy in limited ways.
Legal barriers aside, the request and the official response from the Russian mission appear even more confusing in the light of McCain's overall negative attitude toward Russia.
Last year he said the G8 should exclude Russia, citing "diminishing political freedoms, a leadership dominated by a clique of former intelligence officers, [and] efforts to bully democratic neighbors."
On August 12, during the brief conflict between Russia and Georgia in its breakaway region of South Ossetia, McCain said he had told Georgian President Mikheil Saakashvili: " I know I speak for every American when I say to him, 'Today, we are all Georgians.'''
The Gallup Poll daily tracking survey on Sunday showed Democrat Barack Obama leading McCain nationally by 10 percentage points, 52-42.