The White House on Friday would not rule out invoking executive privilege to try to block fired FBI Director James Comey from testifying before Congress about his conversations with President Trump.

White House press secretary Sean Spicer said the hearing with Comey, scheduled for Thursday at 10 a.m., must be "reviewed" by the White House counsel's office before a decision is made.

"I have not spoken to counsel yet. I don't know how they're going to respond," he said.

Comey is scheduled to testify before the Senate Intelligence Committee, both publicly and behind closed doors.

The ousted director's testimony could cause headaches for Trump, who is facing accusations that he attempted to obstruct the FBI's investigation into Russia's election meddling.

Trump could try to assert privilege to try to block Comey's testimony, but legal experts said such a move might not succeed. It could also generate both political and legal backlash against the president.

Trump has spoken publicly about his talks with Comey. By doing so, he likely waived his ability to invoke privilege, experts say. During those talks, the president allegedly pressured Comey to ease off former national security adviser Michael Flynn and asked for his loyalty.

The White House has denied that Trump said such things. It has also dismissed the notion that any of Trump's associates colluded with Russia in its efforts to interfere with the 2016 presidential election.