Russia has vowed to retaliate against U.S. sanctions imposed on 12 more Russians for alleged human rights abuses.
Washington on May 20 sanctioned 12 Russians for ties to the 2009 death
in prison of human rights lawyer Sergei Magnitsky and other alleged rights abuses.
Magnitsky had exposed massive tax fraud by Russian officials.
The recent sanctions expand a list of individuals targeted under the Magnitsky Act passed by Congress in 2012.
The Russian Foreign Ministry said on May 21 the sanctions were "unfounded and dictated by a cynical desire to use human tragedy for unscrupulous political goals."
It also accused the United States of "double standards" for not speaking out about what it says are abuses by Ukrainian authorities in fighting pro-Russian separatists in the east of the country.
Based on reporting by Reuters and Interfax