"It is deeply troubling that President Trump just fired the person in charge of investigating his ties to Russia." - Sen. Al Franken, D-Minn.
"We need an independent commission and a special prosecutor to get to the bottom of Russian interference in our election." - Sen. Amy Klobuchar, D-Minn.
"Given the recent controversies surrounding the director, I believe a fresh start will serve the FBI and the nation well." - Sen. Lindsey Graham, R-S.C.
"Were these investigations getting too close to home for the president? … This does not seem to be a coincidence." - Sen. Chuck Schumer, D-N.Y.
"Removal … only confirms need for select [committee] to investigate #Russia's interference in 2016 election." - Sen. John McCain, R-Ariz.
"Trump's decision to fire him now, in the midst of an investigation into … ties to Russia is outrageous." - Sen. Ron Wyden, D-Ore.
"We immediately need a special prosecutor to ensure an independent investigation into the Putin-ordered Russian attack on our democracy." - Rep. Tim Walz, D-Minn.