The officials said there have been inter-agency discussions involving the State Department and White House. The sources said the most severe option being considered is for the US to expel more Russian diplomats. One of the officials said that would be a "very serious step," especially given the last round of tit-for-tat expulsions, which left Russia and the US with significantly smaller diplomatic forces in each other's countries. If the US expels more Russian diplomats, in alignment with how the UK has responded to the poisonings, it would be expected that Russia would respond in kind, according to the sources. One official cautioned, however, that expulsions are just one option the White House will consider, and there is not a good sense at this point whether the President will take any action at all.

Source: CNN March 20, 2018 23:15 UTC