The lawyer of Donald Trump’s former “fixer” is walking back claims his client can confirm the US president knew about Russian efforts to interfere with the 2016 election.

Lanny Davis is backpedalling on claims that Michael Cohen could tell a special prosecutor that Mr Trump had prior knowledge of a meeting with a Russian lawyer to get damaging information on Hillary Clinton.

“I should have been much clearer that I could not confirm the story,” Mr Davis said on Monday, attempting to clean up his comments in interviews last week after Cohen pleaded guilty to campaign finance violations, tax evasion and bank fraud.

Michael CohenMichael Cohen was Donald Trump’s former lawyer (AP Photo/Mary Altaffer, File)

Mr Davis told The Washington Post over the weekend that he “could not independently confirm” the claims he made on television last week that Cohen witnessed Mr Trump’s eldest son, Donald Trump Jr, telling his father about the Trump Tower meeting beforehand.

“I take responsibility for not communicating more clearly my uncertainty,” Mr Davis said. “I regret the error.”

Mr Davis is also hedging suggestions he made on television last week that Cohen could tell special prosecutor Robert Mueller about whether Mr Trump was aware of and encouraged Russian hacking during the 2016 campaign before it became publicly known.

After suggesting to US news channel CNN last Wednesday that “Cohen was an observer and was a witness to Mr Trump’s awareness of those emails before they were dropped”, Cohen told the Post: “There’s a possibility that is the case. But I am not sure.”

The prospect of Cohen telling Mr Mueller that Mr Trump knew in advance about the June 2016 meeting has hung over the Russia probe since CNN, citing anonymous sources, reported last month that Cohen was willing to share the information.

Mr Davis told The Associated Press at the time that the basic substance of the CNN report was correct and told CNN last Wednesday that Cohen “was present during a discussion with junior and dad” pertaining to the Trump Tower meeting.

Mr Davis, citing a lack of independent verification, apologised to the AP on Monday. “I express my regrets that I could not confirm what I told you,” he said.

Mr Trump, who has denied knowing about the meeting with Russian lawyer Natalia Veselnitskaya, seized on Mr Davis’ U-turn.

“Michaels Cohen’s attorney clarified the record, saying his client does not know if President Trump knew about the Trump Tower meeting (out of which came nothing!),” Trump tweeted on Saturday. “The answer is that I did NOT know about the meeting. Just another phony story by the Fake News Media!”

CNN said it stands by the story, which included reporting from Pulitzer Prize-winning Watergate reporter Carl Bernstein.

Mr Trump Jr tweeted that CNN was defending “literal fake news” and derided Mr Bernstein as a “leftist hack”.