"We have already said that what has been going on in Ferguson and some other American cities in the past few weeks rings a very serious alarm bell for US authorities. It indicates ruptures in US society on racial and ethnic grounds; conflicts, lines of tension are far from disappearing, they are in fact getting deeper," Konstantin Dolgov said at a conference in Moscow.
"These problems require a great deal of attention from authorities… We expect Washington to heed this call and make certain conclusions," the rights ombudsman said.
Riots flared in the US town of Ferguson in St. Louis County, Missouri, following the fatal shooting of 18-year-old unarmed Michael Brown by a white police officer in August. A second wave of unrest swept 180 cities and 38 states in the United States after the grand jury's decision not to bring charges against law enforcer Darren Wilson who shot him.