Washington( CNN) Republican outraged at Russia's alleged meddling in the US election — and frustrated at some in their own party for not taking on the issue more aggressively — are turning to an unlikely new source of pressure for action: Democrats.

In a letter to Senate Majority Leader Mitch McConnell Sunday, four senior GOP and Democratic senators appealed for a select committee to analyse CIA findings that Russia hacked the elections to help Donald Trump. The idea has so far been rejected by McConnell and House Speaker Paul Ryan, who instead want to see current committees look into the matter.