Russia says the racial unrest in Ferguson highlights "massive" domestic problems in the United States that stem from Washington's failure to respect human rights.

Relations between Moscow and Washington are at a post-Cold War low over a series of disputes, the major one of which is the future of ex-Soviet Ukraine.

Russia's Foreign Ministry says the US should focus more on its own shortcomings instead of getting involved in the fruitless mentoring of other nations.

Moscow has fired almost daily diplomatic barbs at Washington and its European allies since APEC.

President Vladimir Putin was effectively ostracised by other world leaders in Brisbane two weeks ago.