Week of tensions

FBI Director James Comey said in testimony to Congress in March he felt pressure to complete the investigation quickly. Adding to the uncertainty over Clinton is the FBI's refusal to say who is the target of its investigation.

Republican lawmakers have called for an independent investigation, saying they do not trust the Justice Department to handle the inquiry with impartiality. Republicans, including Trump, intensified their criticism of the process on Thursday after news emerged of Lynch's meeting with Bill Clinton.

Lynch said she would accept whatever recommendations the career prosecutors working on the case made about whether to prosecute Clinton.

The FBI probe and the partisan fight over the server have added an extra layer of uncertainty to one of the most tumultuous presidential races in recent memory. Trump, a political novice once dismissed by the Republican establishment, will likely emerge this month as the party's nominee and has set his sights on Clinton, who he has labeled "Crooked Hillary."

Clinton held a nine-point lead over Trump in a Reuters/Ipsos poll released on Friday.