US President Donald Trump said "we can make a fast decision" on a new FBI director, possibly by late next week, before he leaves on his first foreign trip since taking office.
"Even that is possible," Mr Trump told reporters when asked whether he could announce his nominee by Friday, when he is scheduled to leave for the Middle East and Europe.
At least six candidates to be the bureau's director were in line on Saturday for the first interviews with Attorney General Jeff Sessions and his deputy, Rod Rosenstein, at Justice Department headquarters.
They are among more than a dozen candidates Mr Trump is considering, a group that includes several lawmakers, attorneys and law enforcement officials.
"I think the process is going to go quickly. Almost all of them are very well known," Mr Trump said.
"They've been vetted over their lifetime essentially, but very well known, highly respected, really talented people. And that's what we want for the FBI."
The Trump administration is looking to fill the job, which requires Senate confirmation, after Mr Trump abruptly fired director James Comey on Tuesday.
The first candidate to arrive was Alice Fisher, a high-ranking Justice Department official in the George W. Bush administration. She left after about an hour and a half inside the building and declined to comment to reporters.
Among those interviewed was Adam Lee, special agent in charge of the FBI's Richmond, Virginia, office.
Acting FBI director Andrew McCabe also interviewed for the permanent post despite his repeated willingness to break from White House explanations of Mr Comey's sacking and its characterisations of the Russia investigation.
Senator John Cornyn, a former Texas attorney general, was also interviewed.
Among those expected to be interviewed Saturday were Michael J. Garcia, an associate judge on New York's highest court, and US District Judge Henry E. Hudson, a George W. Bush appointee who struck down the centrepiece of the Obama administration's health care law in 2010.
Mr Sessions has faced questions over whether his involvement in Mr Comey's firing violates his pledge to recuse himself from investigations into Russian interference in the election. Some lawmakers have alleged the firing was an effort to stifle that FBI probe.
Justice Department spokeswoman Sarah Isgur Flores said Mr Sessions and Mr Rosenstein are involved in the interviews because the FBI director reports to them as attorney general and deputy attorney general.
They can make recommendations, but the president will ultimately make the hiring decision.