A federal grand jury has reportedly approved the first charges in the investigation into alleged Russian meddling in the 2016 US presidential election.

Key points: Media reports say the details of the probe's first indictment could be revealed next week

Media reports say the details of the probe's first indictment could be revealed next week Former FBI director Robert Mueller is leading the investigation into Russia and the Trump administration

Former FBI director Robert Mueller is leading the investigation into Russia and the Trump administration The reports have not been confirmed by the courts or the investigators

The indictment was sealed under orders from a federal judge, but has been reported by US media outlets citing sources who said they had been briefed on the matter.

It was not clear what the charges were or who the target was, with reports adding the indictment could be unsealed as early as Monday (local time).

US intelligence agencies concluded in January that Russia interfered in the election to try to help President Donald Trump defeat Democratic candidate Hillary Clinton through a campaign of hacking, and disseminating propaganda via social media to discredit her campaign.

Special counsel Robert Mueller, a former director of the Federal Bureau of Investigation, is investigating whether Mr Trump's campaign officials colluded with those Russian efforts.

"If the special counsel finds it necessary and appropriate, the special counsel is authorised to prosecute federal crimes arising from the investigation of these matters," Deputy Attorney-General Rod Rosenstein said in a May 17 letter appointing Mr Mueller.

Sources familiar with Mr Mueller's investigation told US media he had used that broad authority to investigate links between Mr Trump's aides and foreign governments, as well as possible money laundering, tax evasion and other financial crimes.

A spokesman for Mr Mueller declined to comment on the reports.

Mr Trump has denied allegations his campaign colluded with Russians and condemned investigations into the matter as a witch hunt.

The Kremlin has also denied the allegations.

The special counsel's investigation also includes an effort to determine whether the President or any of his aides tried to obstruct justice.

Mr Mueller's team has conducted extensive interviews with former White House chief of staff Reince Priebus, former spokesman Sean Spicer and other current and former White House officials.

In July, FBI agents raided the Virginia home of Mr Trump's former campaign manager, Paul Manafort, whose financial and real estate dealings and prior work for a pro-Russian political party in Ukraine are being investigated by Mr Mueller's team.

Mr Mueller was appointed by the Justice Department to lead the investigation a week after Mr Trump fired FBI director James Comey, who was leading a federal investigation into possible collusion with Russia.

Mr Trump initially said he fired Mr Comey because his leadership of the FBI was inadequate and hurt morale, but in a later interview with NBC he cited "this Russia thing" as his reason.

Reuters