An ex-business partner of former US national security adviser Michael Flynn and a businessman with ties to Turkish government officials have been charged with undisclosed lobbying aimed at the extradition of a Muslim cleric living in the United States.

Flynn's former partner, Bijan Rafiekian, was indicted on two criminal counts, including conspiracy to act as an agent of a foreign government, according to a grand jury indictment unsealed on Monday in the Eastern District of Virginia.

Ekim Alptekin, a Turkish-Dutch businessman, was charged for allegedly plotting with Turkish officials to cause the extradition of Turkish Muslim cleric Fethullah Gulen and for lying to the FBI about his efforts, among six total counts.

A spokesperson for Alptekin said he denied the allegations.

The charges underscored the broadening impact of Special Counsel Robert Mueller's investigation, which is focused on possible collusion between Russia and US President Donald Trump's 2016 election campaign but which has led to at least four spinoff probes including the case against Alptekin and Rafiekian.

Coming on the heels of guilty pleas by former Trump campaign chairman Paul Manafort and political operative Samuel Patten for similar crimes, the indictments also highlight a newfound interest at the Justice Department in enforcing a law requiring disclosure of lobbying for foreign interests.

"I don't think anyone took that law very seriously but perhaps these indictments will change that," said criminal defense lawyer Page Pate.

Flynn, who is due to be sentenced on Tuesday for lying to the FBI related to his contacts with the then Russian ambassador to the United States, Sergei Kislyak, has also admitted to lying about his role in the Turkish lobbying effort and has been cooperating with prosecutors on the probe.

The indictment alleges that Rafiekian and Alptekin made false statements about the project in filings to the Department of Justice in order to mask the involvement of the Turkish government, which had been pushing for the extradition of Gulen, identified only as a Turkish citizen in the indictment.

"The defendants sought to discredit and delegitimize the Turkish citizen in the eyes of politicians and the public, and ultimately to secure the Turkish citizen's extradition," attorneys for the Eastern District of Virginia wrote.

Rafiekian, a former director at the US Export-Import Bank and a co-founder of the Flynn Intel Group (FIG), the consultancy at the heart of the case, made his first appearance on Monday morning at a federal court in Alexandria, Virginia.

Rafiekian's lawyer, Robert Trout, declined to comment.

Alptekin, 41, maintained that he was Flynn's client and not Turkey, a spokesperson said. Alptekin was not in the United States and it was not clear if he would ever challenge the charges in court.

"Ekim remains adamant that he - and he alone - ultimately moved forward with hiring FIG, paying them, and directing their work," Molly Toomey said.

FETHULLAH GULEN

Turkish President Tayyip Erdogan has blamed Gulen for stoking a failed coup against him in 2016 - and his foreign minister grabbed headlines on Sunday by saying that Trump told Erdogan that Washington was working on extraditing the cleric.

A senior White official pushed back on that assertion on Monday, stressing that Trump did not commit during a meeting with Erdogan at the G20 summit two weeks ago to extradite Gulen, who denies involvement in the coup attempt.

The Alliance for Shared Values, a non-profit organization affiliated with Gulen, said in a statement on Monday that the indictments illustrated "just how far the Erdogan government will go in breaking US law."

Flynn's work on the Turkey project came under scrutiny after he published a commentary on a political news website on the day of the 2016 presidential election calling Gulen a "radical Islamist" who should be extradited to Turkey.

Along with the editorial, the Flynn Intel Group produced a report on Gulen and video for a documentary that was never made. Of the roughly $600,000 paid to Flynn's company, $80,000 was sent back to Alptekin through his Netherlands-based firm Inovo BV, Justice Department filings show.

While Alptekin claims the $80,000 was sent back to him as repayment for work that was never completed, the indictment contends the money was part of a pre-arranged plan to kick back 20 percent of the project to Alptekin.

Alptekin, a former chairman of the Turkey-US Business Council, has said the payments to Flynn came from him personally and from Inovo, and were not from the Turkish government.

During an interview with the FBI, Alptekin said that while he had discussed the project with a Turkish government minister he decided to go ahead and retain the Flynn Intel Group himself after the Turkish government "dropped the ball".

Among other evidence, the indictment cites an email from Alptekin to Rafiekian and Flynn in August 2016 in which Alptekin says that he had spoken about the project to discredit Gulen with two Turkish ministers and had a "green light to discuss confidentiality, budget and the scope of the contract."

The indictment also cites a Sept 19, 2016 meeting in New York which sources familiar with the matter said included Rafiekian, Flynn and Turkey's foreign and energy ministers. The latter at the time was Erdogan's son-in-law. The conversation centered on efforts to extradite Gulen, the indictment says.

That conversation was followed in the ensuing weeks by visits by Rafiekian and others to see, among others, a member of Congress and a congressional staffer in an attempt, among other things, to prompt congressional hearings on Gulen.

Reuters