US President Donald Trump is facing the prospect of calls for his impeachment after his personal lawyer sensationally told a federal court he broke election campaign finance laws at Mr Trump’s direction.

Mr Cohen, who once said he would “take a bullet” for the president, pleaded guilty to eight criminal charges of tax evasion, bank fraud and campaign finance violations on Wednesday (AEST), and claimed he acted on Mr Trump’s orders.

He told the court in New York that a presidential candidate directed him to arrange payments ahead of the 2016 election to silence two women who said they had affairs him.

In television interviews, Mr Cohen’s lawyer Lanny Davis later said the longtime Trump confidante had information that would be of interest to special counsel Robert Mueller, who is investigating Russian collusion in influencing the 2016 presidential campaign.

While Mr Cohen did not name Mr Trump in court, Mr Davis later accused the president of being directly involved.

Mr Cohen had “information … regarding both knowledge of a conspiracy to corrupt American democracy by the Russians and the failure to report that knowledge to the FBI,” Mr Davis told MSNBC.

Lanny Davis: "Mr. Cohen has knowledge on certain subjects that should be of interest to the special counsel and is more than happy to tell the special counsel all that he knows." pic.twitter.com/NxPmShwunw

— Maddow Blog (@MaddowBlog) August 22, 2018

He went on to tell CNN that “Cohen has knowledge that would be of interest to the special counsel about whether Donald Trump knew ahead of time about the hacking of emails”.

Mr Davis also said his client would not accept a presidential pardon if Mr Trump offered him one because he wanted no part in what he saw as the president’s abuse of his clemency power.

“He does not want anything from Donald Trump,” Mr Davis told MSNBC.

Mr Cohen’s plea came as former Trump campaign chairman Paul Manafort was found guilty of eight charges in a separate financial fraud trial in Virginia, stemming from a federal investigation into Russian meddling in the 2016.

US media reported that the latest legal developments could pressure Democrats to launch impeachment hearings should they win a congressional majority in the November mid-term elections.

“This is a very big deal,” Neal Katyal, a US solicitor general in the Obama administration and now a white-collar criminal lawyer, was quoted as saying by The Washington Post.

“The President of the United States has been directly implicated in federal crimes, and implicated not by some enemy but by his own personal lawyer,” Mr Katyal said.

Republican strategist Rob Stutzman told The New York Times impeachment considerations would now “define the midterms”.

“It’s inescapable now that Democrats can legitimately raise that issue,” said Mr Stutzman.

Mr Trump angrily lashed out at Mr Cohen late Wednesday night (AEST), claiming the campaign finance violations his former “fixer” pleaded guilty to in New York on earlier that day were “not a crime”, despite prosecutors and Mr Cohen agreeing that they were.

Michael Cohen plead guilty to two counts of campaign finance violations that are not a crime. President Obama had a big campaign finance violation and it was easily settled!

— Donald J. Trump (@realDonaldTrump) August 22, 2018

In a separate tweet, Mr Trump said: “If anyone is looking for a good lawyer, I would strongly suggest that you don’t retain the services of Michael Cohen”.

In a tweet in stark contrast to those referring to  Mr Cohen, Mr Trump said: “I feel very badly for Paul Manafort and his wonderful family. ‘Justice’ took a 12-year old tax case, among other things, applied tremendous pressure on him and, unlike Michael Cohen, he refused to ‘break’ – make up stories in order to get a ‘deal.’ Such respect for a brave man!”

-with agencies