Former aides to Donald Trump's 2016 presidential campaign have been hired to lobby for a Russian-owned ethane company.

American Ethane Company is one of the largest gas companies of its kind, and is partially owned by multiple billionaires with ties to Russian President Vladimir Putin.

The lobbying group is called Turnberry Solutions, which shares a name with Trump's golf course in Scotland.

WASHINGTON — A group of former advisors to Donald Trump's 2016 presidential campaign have been hired to lobby on behalf of a gas company with ties to members of Russian President Vladimir Putin's inner circle, according to a new disclosure form filed on Tuesday.

First flagged by LegiStorm, the group Turnberry Solutions LLC, which was founded by former Trump 2016 campaign aides Jason Osborne and Ryan O'Dwyer, is now lobbying for American Ethane Company. AEC is partly owned by Russian billionaires linked to Putin.

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AEC's majority owner, Konstantin Nikolaev, was also reportedly a financial backer of Maria Butina, the accused Russian spy who infiltrated Republican groups like the National Rifle Association. Andrey Kunatbaev, who was previously a deputy in the State Duma — the lower house of the Federal Assembly of Russia — also owns a stake in AEC.

In addition to Nikolaev and Kunatbaev, Putin's former chief of staff, Alexander Voloshin, also is reported to have a significant financial stake in AEC.

"Ryan O'Dwyer and I were hired to help a US company get permits issued to them to fulfill a contract signed during a signing ceremony between President Trump and President Xi," Osborne said in a statement to CNBC.

AEC is one of the largest ethane companies on Earth and in 2017, signed a $26 billion agreement to send ethane to the Chinese as part of the trade negotiations between Trump and Chinese President Xi Jinping.

"American Ethane is greatly honored to receive this invitation by President Donald Trump and President Xi Jinping," AEC CEO John Houghtaling said in a statement at the time. "As one of the larger deals of this Summit, the agreement meets the US goal of reducing the trade deficit, the China goal of creating for the first time an Ethane-to-Ethylene production in China (an efficient and green industry) and the mutual goal of providing a long term economic link between our two Countries."

AEC CEO John Houghtaling, an American, has said the deal will ultimately benefit the US over Russia.

"I’m quite proud that my Russian partners decided to take huge sums of their money out of Russia and invest it into America, for a deal that will reduce the deficit with China and displace Russian gas," Houghtaling told WWL-TV, a New Orleans-based CBS affiliate, in July.

Turnberry Solutions has a number of clients in addition to AEC. In its bid to purchase Sprint, T-Mobile enlisted Turnberry's lobbying team to seal the deal. At the time, Turnberry also employed former Trump campaign aide Mike Rubino, who took a job at the Department of Health and Human Services.

Rubino left HHS in January because his supervisor Jack Kalavritinos, was "an avowed member of the swamp" and a "never-Trumper," according to Politico.

Turnberry, which is helmed by Osborne and O'Dwyer, shares its name with Trump's golf course in Scotland.