Republicans are not all falling in line behind President Trump after his sudden firing of FBI Director James Comey.

A number of leading GOP senators told reporters Wednesday that they were skeptical of the reasons given for firing the head of the FBI, which since July 2016 has been investigating potential ties between the Trump campaign and the Russian government—a fact revealed by Comey to Congress in March.

While some in the president’s party support his move, many senior Republicans say they are troubled by the current circumstances, and do not understand the justification given for Comey’s dismissal.

“The timing of this, and the reasoning of this doesn’t make sense to me,” said Sen. Richard Burr, the North Carolina Republican who chairs the Senate Intelligence Committee’s investigation into possible Trump-Russia ties. Comey was scheduled to testify before Burr’s committee Thursday, but the chairman told The Daily Beast that, due to his dismissal, Comey will no longer testify.

Sen. Marco Rubio, who ran against Trump in the presidential election, also expressed doubts.

“I don't have any complaints about the way he has performed his job in light of very unique circumstances,” Rubio told The Daily Beast. “It is important that the FBI director has the confidence of the president. On the flip side of it though, there are some questions about the justification for this that I’d want to be able to talk to the White House directly about before I could further opine.”

Comey’s “removal at this particular time will raise questions,” said Sen. Bob Corker, a supporter of Trump and the chairman of the Senate Foreign Relations Committee.

And the chairman of the Senate Armed Services Committee, Sen. John McCain, normally talkative with the press, rushed by while repeating over and over again that he had long called for a select committee to investigate Russian interference.

Just a handful of Republican senators were on the floor Wednesday morning as Majority Leader Mitch McConnell defended the president’s decision.

McConnell said Democrats were hypocritical to criticize Trump when they themselves were unhappy with the way Comey handled the Clinton email investigation—the same rationale, McConnell said, given by Deputy Attorney General Rod Rosenstein in his memo to Comey.

The majority leader was flanked by Sen. John Cornyn, but the Republican side of the body was nearly empty.

Meanwhile, 42 stone-faced Democrats sat quietly behind their desks as Minority Leader Chuck Schumer spoke on the Comey firing.

Schumer, who at times seemed dejected as he repeated much of what has been argued on the Democratic side when it comes to Russia, made the case that there was “little reason to think” that Rosenstein’s letter, which highlighted Comey’s alleged mishandling of the Clinton email server investigation, was the true rationale for Trump to can Comey. If that were true, Schumer argued, Trump would have fired Comey immediately when he took office.

Schumer noted the “very troubling pattern” of firings at the Justice Department since Trump took office, including Acting Attorney General Sally Yates and former U.S. Attorney Preet Bharara. He called on Rosenstein to appoint a special prosecutor who can take the Russia investigation “far away from the heavy hand of this administration.” He also called for a classified briefing for all senators to question both Rosenstein and Attorney General Jeff Sessions.

“Nothing less is at stake than the American people's faith in our criminal justice system and the integrity of the executive branch of our government,” Schumer concluded, warily and dramatically.