On Thursday, President Donald Trump cited Comey's "poor, poor performance" as one reason that he fired Comey. Many Democrats believe that the real reason Mr. Trump pushed Comey out was because of the probe into Russian election interference, and any possible ties to associates of the President.
While Comey agreed to testify before the Senate Intelligence Committee, he evidently decided not to appear before the Senate Judiciary Committee, which left lawmakers on that panel frustrated.
"There is no reason he can’t testify before both the Intelligence and Judiciary Committees," said Judiciary Chair Sen. Charles Grassley (R-IA).
"He should reconsider his decision," Grassley said in a joint statement with Sen. Dianne Feinstein (D-CA).
The latest developments came amid another day of blockbuster news reports about the Russia investigation, and possible ties to the President and his associates.
In one story - which the White House did not dispute - the President reportedly labeled Comey a "nutjob" during a meeting with Russian diplomats, a day after Mr. Trump had fired the FBI Director.