WASHINGTON (Reuters) - An ex-White House official has revised a previous statement by telling investigators that former national security adviser Michael Flynn may have referred to sanctions when they discussed his calls with a former Russian envoy, the Washington Post reported on Saturday.

Retired U.S. Army Lieutenant General Michael Flynn reacts at a campaign event for then Republican presidential nominee Donald Trump in Herndon, Virginia, U.S., October 3, 2016. Picture taken October 3, 2016. REUTERS/Mike Segar

K.T. McFarland’s statement revised an earlier assertion to FBI agents that sanctions on Russia did not come up when she spoke to Flynn in December 2016 about his calls with Sergey Kislyak when he was the Russian ambassador to the United States, the newspaper said, quoting unidentified people familiar with the matter.

Flynn has pleaded guilty to lying to the FBI about his contacts with Russia and is cooperating in the investigation led by special counsel Robert Mueller. He will be sentenced Dec. 18.

Mueller is looking at whether Flynn’s conversations with Kislyak involved what U.S. intelligence agencies say was a Russian influence operation to throw the 2016 presidential vote to then-Republican candidate Donald Trump.

Trump denounces the probe as a “witch hunt” and Russia denies that it meddled in the election.

One question Mueller is investigating is whether Flynn or other Trump aides discussed lifting U.S. sanctions on Russia in exchange for financial considerations.

McFarland’s account does not clarify what the president knew about Flynn’s interactions with Kislyak, the Post quoted its sources as saying.

The newspaper said McFarland did not return requests for comment. Her lawyer, Robert Giuffra, did not immediately return a request for comment.

Flynn, a former Army general who headed the Defense Intelligence Agency, was a Trump campaign aide and briefly served as his national security adviser. He was fired in February 2017 for misleading the administration about his contacts with Kislyak.

Speaking to FBI agents in the summer of 2017, McFarland, who briefly worked as Flynn’s deputy, denied that sanctions arose in her discussions with Flynn about his calls with Kislyak, the Post said.

However, court papers filed in connection with Flynn’s guilty plea indicated that an unidentified Trump transition team member participated in strategising on Flynn’s calls. People familiar with the issue identified the official as McFarland, the newspaper said.

After the papers were filed, investigators again questioned McFarland and she revised her original denial that sanctions arose in her discussions with Flynn, it said.

“She walked back her previous denial that sanctions were discussed, saying a general statement Flynn had made to her that things were going to be OK could have been a reference to sanctions,” the Post reported.

She and Giuffra convinced FBI agents that she did not intentionally mislead them, the newspaper said.