Former US Congressman Anthony Weiner was expected to plead guilty in federal court in New York, months after prosecutors opened an investigation into his alleged "sexting" with a 15-year-old girl that eventually played a role in the US presidential election.
A spokesman for the law firm representing Weiner, Covington & Burling, said he would plead guilty on Friday morning but offered no further details. The charges were not immediately known.
The former Democratic congressman saw his political career implode after a series of scandals involving his inappropriate sexual exchanges with women online. Authorities have been investigating reports that Weiner, 52, sent explicit messages last year to a teenage girl in North Carolina.
Federal agents seized Weiner's laptop during the probe and discovered a batch of emails from his wife, Huma Abedin, a senior aide to Hillary Clinton, the Democratic nominee for president in 2016.
As a result, James Comey, then the director of the Federal Bureau of Investigation, announced in late October that the agency was reviewing the messages to determine whether to reopen its investigation into Clinton's handling of official correspondence.
Clinton has blamed her loss to Republican Donald Trump in part on Comey's announcement, even though Comey said two days before the election in November that the review had uncovered no new evidence.
The controversy centred on Clinton's use of a private email server while she was US secretary of state. Trump and other Republicans accused her of endangering national security by exposing classified information to potential hacking.
In testimony to Congress two weeks ago, Comey said he felt "mildly nauseous" at the suggestion his actions may have swayed the election, but added that he had no regrets.
Trump fired Comey days later amid the FBI's probe into whether Trump's campaign colluded with Russia to defeat Clinton, an allegation he has vehemently denied.
The investigation into Weiner came to light after the Daily Mail, a British newspaper, published an interview with the teen whom Weiner allegedly messaged. It reported that the messages, which began when the girl was a sophomore in high school, indicated Weiner knew she was a minor.