Anthony Weiner

Updated at 12:07 p.m. ET

Anthony Weiner, the disgraced former congressman from New York, pleaded guilty Friday to one charge of transferring obscene material to a minor after he was investigated for sending sexual messages to a 15-year-old girl last year.

Weiner will have to register as a sex offender and could be sentenced to years in prison, The Associated Press reports. As part of his plea deal, he has agreed not to appeal any sentence of 27 months or less, Reuters says.

Weiner cried in court and issued an apology to the teenager, the AP writes.

Updated at 7:58 p.m. ET

Newly discovered emails being examined by the FBI in relation to Hillary Clinton's email server came to light in the course of an unrelated criminal investigation of Anthony Weiner, a source familiar with the matter tells NPR's Carrie Johnson.

Weiner is the estranged husband of close Clinton aide Huma Abedin; he has been under scrutiny for sending illicit text messages to an underage girl. Sources said authorities seized electronic devices in their home, which led them to this new information.