The son-in-law of a Russian oligarch has pleaded guilty to lying to investigators looking into Russian interference in the 2016 US election.

Dutch lawyer Alex Van Der Zwaan, 33, admitted to the US District Court in Washington he misled US Special Counsel Robert Mueller's office about communications with political consultant and lobbyist Rick Gates.

Mr Gates was deputy to Paul Manafort, the former campaign manager for Donald Trump in the run-up to the presidential election, who has also been indicted.

London-based Van Der Zwaan is married to the daughter of German Kahn, a Ukrainian-Russian billionaire who made his money in oil and is one of Russia's wealthiest men.

The lawyer admitted he lied to FBI investigators about conversations related to a report he helped prepare on the trial of a Ukrainian politician, Yulia Tymoshenko, as part of his work for Ukraine's justice ministry.


Image: Alex Van Der Zwaan's charge sheet

Image: He is accused of failing to produce emails sought by the Special Counsel

Van Der Zwaan is also charged with lying about talks with someone named "Person A", who was identified in the Tuesday plea hearing as a colleague of Mr Manafort and Mr Gates who is based primarily in Ukraine.

A representative for Mr Mueller told a judge that Van Der Zwaan communicated with Person A using encrypted messaging.

He will be sentenced on 3 April.

The charge against him made no reference to Mr Trump's campaign or the 2016 election.

Image: Rick Gates was charged with several offences in October 2017

But legal experts said the charge would put more pressure on Mr Gates and Mr Manafort to co-operate with Mr Mueller over the Russian interference investigation.

Mr Manafort and Mr Gates were indicted in October last year as part of Mr Mueller's investigation into Russian meddling.

Both men were charged with 12 counts of conspiracy against the United States, making false statements, money laundering and failing to register as foreign agents for Ukraine.

The charges arose from consultant work for a pro-Russian government in Ukraine.

They both pleaded not guilty, with Mr Manafort released on $10m bond and Mr Gates released on $5m bond and placed under house arrest as they were deemed a flight risk.

Image: Special counsel Robert Mueller is investigating Russian interference in the US election

On 15 February, Mr Gates finalised a plea deal with Mr Mueller's office, indicating he will co-operate in the election investigation.

It is not known if Mr Gates' co-operation led to Van Der Zwaan's indictment.

A total of 19 people have now been charged as part of the investigation, including five US nationals and 13 Russians.

George Papadopoulos, who was on the Trump campaign's foreign policy advisory panel, admitted in October 2017 to making false statements to FBI agents about contacts he had with the Russian government in 2016.

As part of a plea bargain he has been co-operating with the investigation.

Michael Flynn, who was briefly Mr Trump's national security advisor at the start of his presidency, admitted to lying to the FBI about contacts he had with the Russian government during the presidential transition.

He has also been co-operating with the investigation.