A grand jury in Washington has approved the first charges in the probe led by independent prosecutor Robert Mueller, who is investigating any links between Donald Trump's presidential campaign and Russia.

Details of the charges, and who will face them, were not known, but the fact they have been made marked a major step forward in the sweeping investigation into Kremlin interference in last year's US election.

The existence of the charges was first reported by CNN which said a federal judge had ordered that they remain sealed.

Any person charged could be taken into custody as early as Monday.

The Department of Justice, and Mr Mueller's office, declined to comment.

Investigative leads Mr Mueller and his team have looked at include lobbying activities for foreign clients done by Mr Trump's former campaign chairman Paul Manafort, and his former national security adviser Michael Flynn. FBI agents raided Mr Manafort's home in July.

Mr Mueller, a former Director of the FBI, was appointed in May to lead the Russia investigation after Mr Trump fired James Comey as FBI director.

US intelligence agencies concluded in January that Russia interfered in the election to try to help Mr Trump defeat Democrat candidate Hillary Clinton.