Special Counsel Robert Mueller’s investigation into collusion between Russia and the Trump campaign has claimed its first scalp.

Alex van der Zwaan, a Dutch lawyer and the son-in-law of one of Russia’s richest men has been jailed and fined $US20,000 ($26,000) for lying to the investigation about contacts with an official in President Donald Trump’s 2016 campaign.

Mr van der Zwaan who once worked closely with Mr Trump’s former campaign chairman Paul Manafort, was sentenced to 30 days. He must also serve two months of supervised release by a US District Court judge.

Mr van der Zwaan told the court he was sorry for what he did.

He pleaded guilty on February 20 as Mr Mueller ramped up his investigation into potential collusion between Mr Trump’s presidential campaign and Russia.

It marked the first sentencing of anyone in Mr Mueller’s ongoing probe.

In pleading guilty, Mr van der Zwaan admitted that he had lied to FBI agents about previous communications with Rick Gates, a protege of Mr Manafort who held a senior position in the Trump campaign. He also admitted to withholding and deleting emails.

“What I did was wrong. I apologise to this court, and I apologise to my wife,” Mr van der Zwaan said at the sentencing hearing.

Mr van der Zwaan’s attorney, William Jay Schwartz, asked the judge to impose only a fine and allow his client to leave the country, saying he had already been punished enough and should receive credit for returning to the United States last year after lying to Mr Mueller’s investigators to correct the record.

Since his return in December 2017, Mr van der Zwaan has been walled up in a residential hotel in Washington and unable to return to London, where his wife is undergoing a difficult first pregnancy, his lawyer said.

“He is literally in limbo,” Mr Schwartz said.

Mr van der Zwaan, 33, is married to the daughter of prominent Russian billionaire German Khan, founder of the privately owned Alfa Bank.

Mr van der Zwaan previously worked for the law firm Skadden Arps, Slate, Meagher and Flom.

But his apology and Mr Schwartz’s explanations for his client’s actions appeared to ring hollow for the judge.

“This was more than a mistake. It was more than a lapse or misguided moment,” Judge Amy Berman Jackson said.

The judge added that she was disappointed he did not write a letter to the court on his own behalf to express remorse, and said it would not deter others if she merely let him “write a cheque and walk away”.

Mr van der Zwaan worked closely with Mr Manafort and Mr Gates in 2012, before their involvement in the Trump campaign, when they were serving as political consultants for Ukraine’s former pro-Russia President Viktor Yanukovych on a report about former Ukrainian Prime Minister Yulia Tymoshenko.

Former Trump campaign chairman Paul Manafort leaves court last October. Photo: AAP

Mr Mueller has secured two indictments against Mr Manafort arising from his lobbying for the pro-Russian Ukrainian Party of Regions, with charges ranging from failing to register as a foreign agent and conspiring to launder money, to bank fraud and filing false tax returns. Mr Manafort has pleaded not guilty.

Mr Gates pleaded guilty on February 23 to conspiring to defraud the United States and lying to Mr Mueller’s office, and is now cooperating with the probe.

-with AAP