Moscow may expel about 30 American diplomats and seize US property in Russia, according to Russian diplomatic sources. 

The threat of retaliation comes after the US expelled Russian diplomats at the end of last year and seized its diplomatic compounds for alleged meddling in the 2016 US presidential election. 

Russia did not retaliate at the time, apparently at the request of the incoming Trump administration. 

Russian Foreign Minister Sergei Lavrov on Tuesday said it was shameful that the United States had still not resolved the issue.