A lawyer for a prominent law firm is pleading guilty to lying to federal authorities about his interactions with a former Trump campaign associate.

Alex van der Zwaan is entering the plea in court in Washington where he is admitting to lying to special counsel Robert Mueller’s investigators about his interactions with Rick Gates.

Gates is a former aide on President Donald Trump’s campaign and a longtime associate of former Trump campaign chairman Paul Manafort.

The charge against van der Zwaan does not involve election meddling or the Trump campaign’s operations.

It stems from the special counsel’s investigation into a covert Washington lobbying campaign Manafort and Gates are accused of directing on behalf of pro-Russian Ukrainian interests.

Manafort and Gates have pleaded not guilty.

Van der Zwaan is accused of lying to investigators about his interactions with Gates during an interview with the FBI late last year, according to court papers.

His plea comes after an extraordinary indictment from Mr Mueller last week that charged 13 Russian individuals and three Russian companies in a hidden social media effort to meddle in the 2016 US presidential election by denigrating Democrat Hillary Clinton and boosting the chances of Mr Trump.

According to the court filing, prosecutors say van der Zwaan lied about his role in the production of a report on the trial of former Ukrainian prime minister Yulia Tymoshenko.

She is a political enemy of former Ukrainian president Viktor Yanukovych, whose political party was a client of Gates and Manafort.

Van der Zwaan is accused of lying during an interview with prosecutors and FBI agents on November 3 2017, about the timing of his last communication with Gates and an unidentified person described as “Person A”.

The report was written by the law firm, Skadden, Arps. Van der Zwaan’s now-defunct LinkedIn page lists him as an associate in its London office.

On Tuesday, Skadden Arps released a statement saying it had fired van der Zwaan last year. The firm said it “has been co-operating with authorities in connection with this matter”.

It did not say what led to the firing. The charging document notes that the emails van der Zwaan is accused of deleting and withholding from the special counsel’s office were also sought by the law firm, which is referred to as “Law Firm A”.

Last year, van der Zwaan married the daughter of Ukrainian-Russian billionaire German Khan, according to the Russian editions of Forbes and Tatler magazines.

The lavish wedding to Khan’s daughter, Eva, was held at Luton Hoo, a historic mansion-turned golf hotel in Buckinghamshire.

The three-day event included a Russian party complete with a Cossack choir and guests dressed in Russian folk costumes, according to the magazines.

Mr Khan, who was born in Kiev, shares control of one of Russia’s biggest financial and industrial investment conglomerate, Alfa Group, with fellow billionaires Mikhail Fridman and Alexei Kuzmichev.

Forbes estimates he is worth 10 billion US dollars (£7.1 billion).

Mr Khan and his partners are suing Buzzfeed News over its publication of a dossier of allegations about ties between Mr Trump and Russia.

The dossier, which was written by former British spy Christopher Steele, makes several claims about Alfa Group that the partners say are false and defamatory. Buzzfeed is fighting the lawsuit.

The dossier has become a political lightning rod because Mr Steele’s work was funded in part by Mrs Clinton’s campaign and the Democratic National Committee.

Parts of Mr Steele’s work were also used in obtaining a secret warrant to monitor Carter Page, a former Trump campaign foreign policy adviser.