WASHINGTON — The FBI has obtained a warrant to search the emails found on a computer used by former Rep. Anthony Weiner that may contain evidence relevant to the investigation into Hillary Clinton's private email server, the Washington Post reported Sunday, citing unnamed law enforcement officials.

One official said the total number of emails recovered in the Weiner investigation is close to 650,000 — though that reflects many emails that are not in any way relevant to the Clinton investigation. Officials familiar with the case said, though, the messages include a significant amount of correspondence associated with Clinton and her top aide, Huma Abedin, Weiner's estranged wife.

The agents investigating the Democratic presidential nominee's use of a private email server while she was secretary of state knew early this month that messages recovered in the Weiner inquiry might be germane to their case, but they waited weeks before briefing the FBI director, according to people familiar with the case.

FBI director James Comey has written that he was informed of the development Thursday, and he sent a letter to members of Congress the next day letting them know that he thought the team should take "appropriate investigative steps designed to allow investigators to review these emails."

That missive ignited a political firestorm less than two weeks before the election. Almost instantly, Comey came under intense criticism for his timing and for bucking the Justice Department's guidance not to tell Congress about the development. And his announcement means that Clinton could have to contend with the news that the FBI has resumed its investigation of her use of a private email server — without any real clarity on if its investigators will actually find anything significant — up to and beyond Election Day.

People familiar with the case said they had known about the messages since soon after New York FBI agents seized a computer related to their investigation into Weiner, the former Democratic representative from New York who is alleged to have exchanged explicit messages with a 15-year-old girl.

Abedin has told people that she is unsure how her emails could have ended up on a device she viewed as belonging to her husband, according to a person familiar with the investigation and civil litigation over the matter.

An announcement from the FBI in early October, when the emails were discovered, might have been less politically damaging for Clinton than one coming less than two weeks before the Nov. 8 election. It is also unclear what agents have been doing in the intervening time — for instance, whether they were trying to learn more about the emails before notifying Comey. An FBI spokesman declined to provide a statement.

Comey wrote in his letter to Congress, "We don't know the significance of this newly discovered collection of emails," and federal law enforcement officials have said that investigators on the Clinton email team still had yet to thoroughly review them. They would need a warrant to do so, and as of late Saturday, they had not yet acquired one, according to an official familiar with the case.

Why authorities had not yet obtained a warrant also is unclear.

Comey in July announced that he was recommending the investigation into Clinton's use of a private email server while she was secretary of state be closed without charges. But he said investigators had found classified information on the server and characterized Clinton's and her aides' conduct as "extremely careless."

Legislators on both sides of the political aisle are likely to raise questions about why the team investigating Clinton's private email took so long to brief Comey. Clinton and her backers have pushed aggressively for the bureau to release more information about its findings and criticized the agency for making its work public without knowing more.

Republican presidential nominee Donald Trump has called the matter "the biggest scandal since Watergate" and suggested, without evidence to support it, that the case against Clinton was now "so overwhelming."

"We never thought we were going to say thank you to Anthony Weiner," Trump quipped at a campaign rally Sunday in Las Vegas. Several supporters chanted "Weiner! Weiner!" when Trump mentioned the disgraced former representative.

"As you've heard, it was just announced on Friday that the FBI is reopening their investigation into the criminal and illegal conduct of Hillary Clinton," Trump said during his rally. "Hillary has nobody but herself to blame for her mounting legal problems. Her criminal action was willful, deliberate, intentional and purposeful."

Campaigning in South Florida on Sunday, Clinton made no direct mention of the FBI controversy, but on several occasions she seemed to allude to it.

"I want you to know, I am focused on one thing: you, the problems that keep you up at night," Clinton said during an event in Wilton Manors. "There's a lot of noise and distraction, but it really comes down to what kind of future we want."

The email controversy also was the focal point of interviews with Trump and Clinton surrogates on the Sunday morning political shows.

Trump's running mate, Indiana Gov. Mike Pence, said that he feels "tremendous momentum in this campaign" during an appearance on Fox News Sunday and said that Trump would likely inject more of his personal wealth into his campaign in the remaining days.

Clinton and other Democrats were hitting hard at Comey, attacking his announcement as inappropriate and unfair this close to Election Day.

Clinton's running mate, Sen. Tim Kaine of Virginia, called the FBI announcement "extremely puzzling" during an interview on ABC's This Week.

Senate Minority Leader Harry Reid, R-Nev., went further on Sunday, accusing Comey of breaking federal law. The senator said in a letter sent to Comey that his disclosure to Congress about the email inquiry might have violated the Hatch Act, which prohibits partisan politicking by government employees.

The FBI did not immediately respond to an email seeking comment on Reid's letter.