Comey said Thursday that he believes — based on the president’s own words — that Trump fired him in some way because of the FBI’s ongoing investigation into potential coordination between Russia and the Trump campaign.

“It’s my  judgment that I was fired because of the Russia investigation,” Comey said. “I was fired in some way to change, or the endeavor was to change, the way the Russia investigation was being conducted.”

Comey said this was “a very big deal,” not only because of the FBI’s investigation. He also said it was “a very big deal” if any Americans were involved in coordinating with the Russians.

When asked by Sen. Jack Reed (D-R.I.) about his firing, Comey noted there were public reasons offered by the White House for his firing — including claims that it was due to his handling of the Hillary Clinton email investigation and another suggestion that the FBI was in disarray due to his leadership.

“There was an explanation, I just don’t buy it,” he said of the official, and shifting, White House line.