"Today, former Congressman Anthony Weiner admitted and pled guilty to sending sexually explicit images and directions to engage in sexual conduct to a girl he knew to be 15 years old", acting US Attorney Joon H. Kim of the Southern District of NY said in a statement.
September 21: The DailyMail.com publishes an interview with a 15-year-old girl who claims she had sexually explicit online text and video exchanges with Weiner.
As part of the plea deal, Weiner agreed to a sentence of 21-27 months in prison and to registering as a sex offender.
The official wasn't authorized to speak about the plea bargain because the criminal charges had yet to be filed publicly with the court and spoke to The Associated Press on condition of anonymity.
The Democratic former congressman apologized to the 15-year-old, saying, "I have a sickness, but I do not have an excuse".
Weiner admitted that in 2016, he started up an online relationship with the North Carolina teen "who said she was a high school student" after she contacted him online. "I am filled with regret and heartbroken for those I hurt".
"I knew that was morally wrong", Weiner said, breaking down in tears. He faces between no jail time and ten years at sentencing, it said.
Weiner was already in federal custody ahead of the hearing, which lasted less than half an hour.
Arlo Devlin-Brown, an attorney at Covington & Burling, said Weiner accepted "full responsibility" for his "inappropriate" actions, adding that Weiner would not further address the matter.
Abedin, a top aide to Democratic presidential candidate Hillary Clinton a year ago, separated from Weiner in September after revelations he had sent more sexually charged messages online.
The sexting case unexpectedly played a prominent role in the election, after investigators looking into Weiner's laptop found some of Abedin's work emails.
In late October, just days before the election, FBI Director James Comey stunned the country by announcing that his agency was reopening its closed investigation into Clinton's handling of State Department business on a private email server so it could analyze the newly discovered correspondence.
Weiner resigned from Congress in 2011 in the wake of a sexting scandal.
Weiner ran unsuccessfully for mayor of NY in 2013 in a campaign that collapsed when Weiner, using the alias "Carlos Danger", again was found to be sending explicit photographs.
Clinton believes the hit her campaign took from the revelation led her to lose the election to Donald Trump.
Weiner also claimed at the time that he was "likely" the subject of a hoax.