US President Donald Trump’s former lawyer Michael Cohen has pleaded guilty to lying to Congress in relation to the Russia inquiry.

Mr Cohen admitted misleading lawmakers about talks over a Trump property deal in Moscow during the presidential race.

Mr Trump said his former right-hand man was “lying” to seek a reduced sentence.

In August, Mr Cohen pleaded guilty to violating finance laws during the 2016 presidential election by handling hush money for Mr Trump’s alleged lovers.

Thursday’s hearing was the latest twist in the US Department of Justice special counsel’s investigation into whether Mr Trump or his inner circle colluded with a Russian attempt to influence the 2016 presidential election.

What did President Trump say?

As he left the White House for a G20 summit in Buenos Aires, Mr Trump told reporters of Mr Cohen: “He’s a weak person and not a very smart person.

“He’s got himself a big prison sentence. And he’s trying to get a much lesser prison sentence by making up this story.”

Mr Trump told reporters of the Moscow real estate project, which never came to fruition: “When I’m running for president that doesn’t mean I’m not allowed to do business.”

He added: “He’s lying about a project that everybody knew about. I mean, we were very open with it.”

President’s political nightmare worsens

Analysis by Anthony Zurcher, BBC News, Washington

Up until now, Michael Cohen had been a tangential figure in Donald Trump’s Russia-related headaches. After his plea agreement with the special counsel’s office, however, he’s now smack dab in the middle of Robert Mueller’s probe.

In particular, Cohen is sharing information with the special counsel about Mr Trump’s Russian business interests – including efforts to build a Trump Tower in Moscow – which, according to the president’s former personal lawyer, continued well into Mr Trump’s presidential campaign.

That runs counter to the president’s continued insistence that he had no financial ties to Russia – an assertion he frequently made when questioned about his past praise of Russian President Vladimir Putin and efforts to improve US-Russian relations.

If Mr Cohen can provide evidence supporting his claims it would be a political nightmare for the president and, if Mr Trump made false claims in his recent written testimony to Mr Meuller, a legal one, as well.

The president has been tweeting furiously about the special counsel team in recent days, and given the steady drumbeat of news on Mr Mueller’s investigation, it feels as though a crescendo is approaching.

What happened in court?

Appearing unexpectedly before a federal judge in Manhattan on Thursday morning, Mr Cohen, 52, pleaded guilty to one count of making false statements to Congress.

He said at the hearing that he had submitted a false written statement about a Trump Organization plan to build a skyscraper bearing Mr Trump’s name in the Russian capital.

“I made these misstatements to be consistent with individual 1’s political messaging and out of loyalty to individual 1,” Mr Cohen said in court, according to Reuters news agency.

He has previously identified “individual 1” as Mr Trump.

Mr Cohen was interviewed in October last year behind closed doors by lawmakers conducting their own investigation into whether Mr Trump’s campaign worked with Russia to sway the US election two years ago.

According to the criminal complaint, he told the Senate and House intelligence committees that talks over the Moscow project had lasted from September 2015 until January 2016, while Mr Trump was campaigning for US president.

But the criminal complaint says that “as Cohen well knew” negotiations over the Moscow project continued until June 2016.

Mr Cohen also told lawmakers he had had limited contact with Mr Trump about the project, when in fact it had been “more extensive”.

Prosecutors said Mr Cohen had tried to give a false impression that the Moscow project ended before the Republican presidential campaign properly began in 2016 with the Iowa caucus.

In a press scrum outside court moments after the hearing, Mr Cohen said nothing to reporters.

But his lawyer said: “Mr Cohen has co-operated. Mr Cohen will continue to co-operate.”

What else has Cohen admitted?

Mr Cohen once famously vowed he would take a bullet for Mr Trump, but in April this year his home and office were raided by the FBI.

In August, Mr Cohen, who had been Mr Trump’s personal lawyer for more than a decade, pleaded guilty to eight criminal charges, including tax evasion, bank fraud and campaign finance violations.

He said he had paid hush money to two women who alleged they had affairs with Mr Trump, at the direction of “the candidate”, clearly implicating Mr Trump.

Undisclosed payments to bury embarrassing stories about a political candidate can be treated as a violation of US campaign finance laws.

In September, Mr Cohen’s lawyer said his client had been providing “critical information” to special counsel Robert Mueller’s investigation.

What else is going on with the Mueller inquiry?

It has been a busy week for the special counsel.

On Monday, his prosecutors said in a court filing that former Trump campaign chairman Paul Manafort had lied to them, breaching a plea agreement.

Mr Manafort has already pleaded guilty to a range of charges from money laundering to unregistered lobbying.

On Thursday, Mr Trump said he had not ruled out granting a pardon to Mr Manafort.

“It is sad what happened to Paul [Manafort], the way he is being treated,” said the Republican president.

He said he had not explicitly offered a pardon to Mr Manafort, but: “I’m not taking anything off the table.”

Mr Mueller has already brought criminal charges against a series of former Trump aides and associates, including his former national security adviser Michael Flynn, Russian individuals and entities.

The inquiry is ongoing, but no hard evidence of collusion between the Trump campaign and the Kremlin has so far emerged.