NEW YORK (AP) — The Washington publication The Hill issued a lengthy report on Wednesday finding fault with several articles by journalist John Solomon that it published last year and were used as discredited narratives by President Donald Trump and many of his supporters in their fight against impeachment.

The Capitol Hill publication, in an internal review, found fault with how its own journalists failed to point out distinctions between news and opinion pieces and didn’t disclose conflicts of interest to readers.

The Hill stopped short of retracting or apologizing for Solomon’s work. It has not erased the pieces from its website but added editor’s notes that questioned the credibility of some of his sources and what they told him.

Bob Cusack, the publication’s editor-in-chief, did not immediately return phone messages.

Solomon reported that a Ukrainian prosecutor had opened an investigation into alleged attempts by Ukrainians to interfere in the 2016 U.S. election on behalf of Democrat Hillary Clinton, a false story spread by Russians to deflect from their own involvement on behalf of Trump. The prosecutor, Yuriy Lutsenko, also said that U.S. Ambassador Marie Yovanovitch had given him a list of officials not to prosecute for corruption. The State Department denied this at the time and Lutsenko later recanted his claims.

In later testimony in Trump’s impeachment investigation, the articles on Yovanovitch were described as part of a smear campaign set in motion by Trump’s lawyer, Rudolph Giuliani.

Solomon also falsely suggested that former Vice President Joe Biden had intervened in Ukraine to protect his son Hunter, who worked on the board of Burisma, a Ukrainian energy company, the review said.

Solomon, who had worked at The Associated Press, The Washington Post and The Washington Times, joined The Hill in 2017 in an executive role but also wrote stories that the publication began identifying as opinion, not news. He has defended his work in the past. He was unavailable for comment due to a death in the family, but is exploring legal options, said his representative, attorney C. Boyden Gray.

In the review published Wednesday, the Hill said readers could have easily misunderstood that Solomon’s stories, since they contained quotes and reached out to multiple sources, were news stories. That distinction also wasn’t made clear when Solomon discussed his stories on Fox News Channel.

“The Hill did not contact television producers to label Solomon as an opinion columnist,” the newspaper wrote. “It should have.”

The review faulted Solomon for not disclosing that he used his own lawyers, Joseph diGenova and Victoria Toensing, as sources, and not revealing that some other sources had been indicted or were under investigation.

The Hill also said that Solomon had improperly sent a copy of one article to his lawyers and Lev Parnas, a Ukrainian American who was another source, prior to publication without the knowledge of his editors. Solomon has said he has done this routinely to check accuracy, but the Hill said it does not condone the practice.

The Hill, noting its own mistakes in dealing with Solomon’s work, said it would write ethics guidelines to distribute to its staff.