US special counsel Robert Mueller has charged at least one person in the sprawling probe over Russian interference in last year's presidential vote, marking the start of a new judicial phase.

Details of the first charges as well as the target remain unclear at this stage, but CNN confirmed with several sources briefed on the matter that a federal grand jury on Friday had approved them -- and arrests could take place as early as Monday.

At least one person is in the legal crosshairs, according to The Wall Street Journal.

Reached by AFP, both Mueller's office and the US Department of Justice have declined to comment on the reports.

Mueller, a former FBI director, was tapped in May to head the Russia probe shortly after Trump's shock sacking of then-FBI director James Comey.

Until then the FBI had been conducting a probe it launched in July 2016. After Comey's dismissal the Justice Department's second-in-command Rod Rosenstein appointed Mueller to take the reins as special counsel -- a role more independent than a normal prosecutor but still under supervision of the department.

The sweeping investigation encompasses all Russian attempts to sway the 2016 US presidential election, including possible collusion with members of Donald Trump's campaign.

The president has denied any collusion with Moscow.

Team Mueller is also scrutinizing whether Trump -- who admitted to firing Comey over the Russian affair -- obstructed justice.

In bombshell testimony before Congress the ex-FBI chief said the president pressured him for loyalty and urged him to drop a probe into former national security advisor Michael Flynn.

- Counter-attack on Clinton -

Trump's former campaign chairman Paul Manafort is among those of interest to investigators, particularly over financial links to Russia he developed as a lobbyist and consultant.

Flynn is also under the magnifying glass for alleged lobbying activities for Turkey. He was forced out just 22 days into the new administration, and is also under investigation for misreporting contacts with Russian officials during the presidential race.

The looming arrests sparked a wave of indignation among Trump's backers, who -- like the president himself -- consider Mueller's probe a "witch hunt."

Sean Hannity, a star Fox News anchor and fervent supporter of the president, has alleged that the federal investigation is a smokescreen intended to mask another scandal involving former Trump rival Hillary Clinton.

"When will @HillaryClinton be indicted?" the favorite among conservatives tweeted.

Republican lawmakers recently opened a probe targeting the Obama administration's approval of the sale of Canadian mining company Uranium One, which owns several US mines, to Russian state-owned company Rosatom.

They accuse Clinton, then secretary of state, of letting the sale go through in exchange for donations to the Clinton Foundation.

Reports also came out this week that Clinton's presidential campaign and the Democratic National Committee helped fund research for a salacious dossier on Trump's alleged compromising links to Russia.

Trump has branded the files -- which leaked to the press in January -- as "fake news."

Democrats dub both issues as obvious attempts at diversion, particularly that of the uranium deal which has been publicly dissected for years.

The White House, however, has missed no opportunity to accuse Clinton of Russian collusion.

"I think we're starting to now see that all of the things that the Democrats had accused this President of doing, they were actually guilty of themselves," said White House spokesperson Sarah Huckabee Sanders Friday.

Source: AFP