Sen. John McCain, R-Ariz., on Tuesday evening said allegations against President Trump's administration have reached a "Watergate size and scale."

McCain, who has not been an ardent supporter of Trump, made the comment at an International Republican Institute panel in Washington, D.C., according to reporters who attended.

Trump has been lambasted with accusations over the past week. Last week, he abruptly fired former FBI Director James Comey, which concerned some because of the agency's investigation into Russia and his campaign.

On Monday, a report stated Trump shared highly classified national security information with Russian government officials. By Tuesday, another report surfaced claiming Trump told Comey to end the FBI investigation into former National Security Adviser Mike Flynn.