Manafort arrived at the Federal Bureau of Investigation Washington field office, television video showed. He was to surrender to federal authorities, the New York Times and CNN reported, citing sources.
The charges against Manafort would be the first arising from the investigation by Justice Department special counsel Robert Mueller, who was appointed to look into alleged Russian meddling to sway the election in favor of Trump.
The charges against Manafort would include tax fraud, according to the Wall Street Journal.
A federal grand jury issued the indictment on Friday and a federal judge ordered it sealed, a source briefed on the matter told Reuters, adding it could be unsealed as soon as Monday.
Manafort associate Rick Gates would also surrender, the Times reported.
Lawyers for Gates and Manafort would not immediately return calls for comment.
Manafort, 68, served the Trump campaign from June to August of 2016 before resigning amid reports he may have received millions in illegal payments from a pro-Russian political party in Ukraine.
Mueller has been investigating Manafort's financial and real estate dealings and his prior work for that political group, the Party of Regions, which backed former Ukrainian leader Viktor Yanukovich, sources have told Reuters.
Investigators also examined potential money laundering by Manafort and other possible financial crimes, according to the sources.
Trump has denied any allegations of collusion with the Russians and called the probe "a witch hunt." The Kremlin also has denied the allegations.
Just before the Manafort report came out, Trump senior adviser Kellyanne Conway insisted any charges would not necessarily implicate Trump or his campaign.
"Whatever happens today with the Mueller investigation, we don't even know that it has anything to do with the campaign ...," Conway said on Fox.
The Russia investigation has cast a shadow over Trump's 9-month-old presidency and widened the partisan rift between Republicans and Democrats.
U.S. intelligence agencies concluded in January that Russia interfered in the election to try to help Trump defeat Democrat Hillary Clinton by hacking and releasing embarrassing emails and disseminating propaganda via social media to discredit her.
Mueller is also investigating whether Trump campaign officials colluded with the Russian efforts.
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