"The president's power to assert executive privilege is very well established", Sanders said.
Comey is scheduled to testify Thursday before the Senate intelligence committee. Could President Donald Trump keep Comey from testifying to lawmakers about their priv.
He will face a barrage of questions from Republican and Democratic lawmakers about the circumstances of his firing, as well as allegations that Trump tried to get Mr Comey to shelve the investigation of his aides.
Donald Trump will not use presidential powers to prevent ex-FBI director James Comey from testifying to Congress on Thursday, the White House said, setting the stage for potentially explosive testimony later this week.
Associates of Comey said the former director kept notes of his conversations with Trump, including of a February meeting in which the president asked Comey to lay off an ongoing investigation into former national security adviser Michael Flynn - a topic that is sure to come up at the hearing.
Comey's testimony probably will focus on the private meetings the former Federal Bureau of Investigation director had with Trump and subsequently chronicled in internal memos and recounted to associates who have divulged their contents to The Associated Press and other media outlets.
Trump to date has limited his socializing to the White House and his Trump-branded properties.
Executive privilege is a presidential power that stems from the idea that the commander-in-chief should be able to enjoy honest conversations with his aides and advisers.
Ronald Reagan is the most recent president to skip the dinner thrown by the White House press corps.
Trump asked Comey to drop the Flynn investigation, said a person who was given a copy of a memo Comey wrote about the conversation. He cant put somebody in jail for violating executive privilege, and he cant fire him, because hes already been fired.. "Arguably, Trump has himself breached that confidentiality", Harvard Law professor Noah Feldman said in a Bloomberg op-ed.
Mr Comey's sacking came as the Federal Bureau of Investigation probes possible collusion between the president's election campaign team and Russian Federation - which United States intelligence believes hoped to tilt the election in the Republican's favor.
Correction: Noah Feldman's statement originally appeared in a Bloomberg op-ed.