By Sarah N. Lynch

WASHINGTON (Reuters) - The U.S. special counsel who is investigating alleged Russian interference in the 2016 presidential election has charged an attorney with lying about his communications with Rick Gates, a former aide to Donald Trump's campaign.

Special Counsel Robert Mueller unsealed criminal charges on Tuesday against lawyer Alex van der Zwaan for allegedly lying to the FBI last November about work his law firm performed in 2012 related to Ukraine.

The charge likely puts pressure on Gates and Trump's former campaign manager Paul Manafort, who are both facing criminal charges including conspiracy to launder money and failure to register as foreign agents in connection with their political work for a pro-Russia Ukrainian party.

They have pleaded not guilty. A trial is tentatively expected this fall, though recent media reports have said that Gates is expected to plead guilty in the near future.

Mueller is investigating whether the Trump campaign colluded with Russia during the 2016 election. Trump says there was no collusion and Russia denies meddling with the election.

The charging documents released on Tuesday say van der Zwaan made false statements about the last time he communicated with Gates and another unnamed person, only identified as "Person A."

He allegedly told investigators he did not know why an email between him and Person A was not produced to the Special Counsel's office, but had actually deleted or failed to produce emails that were being sought.

Van der Zwaan will appear in court later Tuesday for a plea hearing.

The case against him underscores the extent of Mueller’s probe and of his interpretation of how far he can investigate as he looks into whether Russia tried to influence the election in favor of Trump by hacking the emails of leading Democrats and distributing disinformation and propaganda online.

Manafort has argued the charges against him fall outside of Mueller's jurisdiction, because they have nothing to do with Trump's election.

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Tuesday's court filing does not name the law firm that van der Zwaan worked for, though a 2012 report on former Ukrainian Prime Minister Yulia Tymoshenko that it cited was penned by the prominent international law firm Skadden, Arps, Slate, Meagher & Flom LLP.

In a statement on Tuesday, a spokeswoman for the firm said it had terminated van der Zwaan's employment in 2017 and "has been cooperating with authorities in connection with this matter."

(Reporting by Sarah N. Lynch, Doina Chiacu and Jonathan Landay; Editing by Alistair Bell)