An ABC News reporter who erroneously reported a crucial detail following the guilty plea of Michael Flynn has been suspended for a month without pay, the news organization said Saturday.

Brian Ross, a longtime investigative reporter at the network, reported Friday morning during a special report that Flynn had been directed to contact Russian officials by then-candidate Donald Trump during the presidential campaign. When pleading guilty, Flynn admitted to lying about contacts with the Russian ambassador to the U.S. during the presidential transition period, but filings from the office of Special Counsel Robert Mueller did not allege any contacts during the campaign itself, or implicate Mr. Trump directly.

The Dow Jones Industrial Average tumbled more than 300 points following Ross' report, which was not matched by other major news organizations.

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ABC News issued a "clarification" later Friday walking back the report.

CORRECTION of ABC News Special Report: Flynn prepared to testify that President-elect Donald Trump directed him to make contact with the Russians *during the transition* -- initially as a way to work together to fight ISIS in Syria, confidant now says. https://t.co/ewrkVZTu2K pic.twitter.com/URLiHf3uSm — ABC News (@ABC) December 2, 2017

In a statement Saturday, the network said "the reporting conveyed by Brian Ross during the special report had not been fully vetted through our editorial standards process," calling the erroneous report a "serious error."

"As a result of our continued reporting over the next several hours ultimately we determined the information was wrong and we corrected the mistake on air and online," ABC said. "It is vital we get the story right and retain the trust we have built with our audience -- these are our core principles. We fell far short of that yesterday. Effective immediately, Brian Ross will be suspended for four weeks without pay."