Moscow will respond in kind to U.S. sanctions imposed on Russian officials over the Crimea dispute and is considering other steps if Washington escalates tensions, Deputy Foreign Minister Sergei Ryabkov said on Wednesday.
On Monday, the United States and the EU announced sanctions on a handful of officials from Russia and Ukraine accused of involvement in Moscow's seizure of Ukraine's Crimea region, most of whose 2 million residents are ethnic Russians.
Washington has threatened further sanctions while Russian lawmakers raced to ratify a treaty making Crimea part of Russia by the end of the week.
"We are looking at a broad range of responsive measures. They can be identical measures regarding certain lists of American officials - not necessarily representatives of the administration ... who have influenced American policies," Ryabkov was quoted as saying by Interfax.
"There is also the possibility of passing asymmetrical measures, that means steps which, let's say ... won't go unnoticed in Washington," he said.
Russian Foreign Minister Sergei Lavrov has called the sanctions "unacceptable."
But some of the Russians included on the list of individuals have scoffed at the measures which would freeze their assets in the United States.
Ryabkov gave few details on what form those measures could take but suggested that six-party talks over Iran's nuclear program could provide a means of response.
"Moscow would not want to use these talks as an element of raising the diplomatic stakes," he said. "But if we are forced, we will follow here a path of responsive measures because in the end the historical importance of what has happened in the last days and weeks regarding the ... reunification of Crimea with Russia is incomparable to what we are doing regarding Iran."
