A former U.S. congressman is due to stand trial starting on Monday on charges of illegally lobbying U.S. officials to prevent further economic sanctions against ousted Venezuelan President Nicolas Maduro's government.

Federal prosecutors in Miami say David Rivera was paid $20 million in 2017 by Venezuelan state-owned companies to try to improve U.S.-Venezuela ties, but did not register as a foreign lobbyist as required by the Foreign Agents Registration Act.

The trial could shed light on the behind-the-scenes role Venezuela's current interim President Delcy Rodriguez played in the alleged lobbying effort during the early days of President Donald Trump's first term in the White House.

Trump has praised Rodriguez since she took over from Maduro following his Jan. 3 capture by U.S. special forces.

Rivera has pleaded not guilty to 10 criminal counts including failure to register as a foreign agent and conspiracy to commit money laundering.

The 60-year-old Republican, who represented southern Florida in the U.S. House of Representatives from 2011 to 2013, was arrested in 2022 and has since been free on $200,000 bond.

Prosecutors have said they may call U.S. Secretary of State Marco Rubio, a former U.S. senator and onetime political ally of Rivera's, as a witness. The trial is expected to last several weeks.

Rivera's defense lawyer Ed Shohat told Reuters in a telephone interview that Rivera did not have to register under FARA because he was paid by a U.S. affiliate of Venezuelan state oil company Petroleos de Venezuela.

In court papers, Rivera's lawyers have argued that he was working to help Venezuela's opposition remove Maduro from power.

"The prosecutors in this case have it completely wrong and backwards," lawyers for Rivera and his co-defendant, political consultant Esther Nuhfer, wrote in a court filing made public in January. Nuhfer has also pleaded not guilty.

According to the indictment, a Venezuelan businessman in February 2017 sought Rivera's help with lobbying U.S. officials on the Venezuelan government's behalf.

At the time, Venezuela was undergoing an economic crisis, Maduro's government was cracking down on street protests, and his opponents accused him of sidelining the opposition-controlled legislature. U.S. lawmakers were urging Trump to step up pressure on Maduro.

Rivera in April arranged for a meeting between Rodriguez, then Venezuela's foreign minister, and a U.S. congressman from Texas, prosecutors said. In June 2017 he arranged a meeting between the businessman and a U.S. senator from Florida, according to the indictment.

The indictment did not name the businessman, congressman or senator. Rivera's lawyers identified the businessman and senator in other court papers as Raul Gorrin and Rubio, respectively.

A lawyer for Gorrin, the owner of Venezuelan television station Globovision, did not respond to a request for comment.

The State Department did not respond to a request for comment.

To compensate Rivera, Rodriguez directed U.S. oil refiner Citgo, a PDVSA subsidiary, to sign a consulting contract with his company, prosecutors said.

Venezuela's information ministry, which handles media inquiries for the government, did not respond to a request for comment.

Trump ramped up sanctions on Venezuela despite the alleged lobbying effort. (Reporting by Luc Cohen in New York; Additional reporting by Humeyra Pamuk in Washington and Caracas newsroom Editing by Noeleen Walder and Nia Williams)