Mueller says Russians are altering evidence from special counsel’s investigation to discredit the probe

Documents were allegedly altered and then leaked online

Robert Mueller is said to be nearing the end of his investigation into Russian interference in the US election (AP)

Russians have obtained evidence from special counsel Robert Mueller’s inquiry into Moscow’s interference in US politics and altered it in a bid to discredit the probe, federal prosecutors have claimed.

The files were shared with attorneys working for Concord Management and Consulting, a Russian company that allegedly funded hacking operations by Russia’s Internet Research Agency (IRA), they said in a court filing.

The sharing evidence and documents between prosecutors and defence lawyer as part of routine discovery is common legal practice.

But the files shared by Mr Mueller's investigation were later uploaded and disseminated on Twitter in October.

However, the files shared online, "appear to have been altered and disseminated as part of a disinformation campaign aimed (apparently) at discrediting ongoing investigations into Russian interference in the US political system,” the court filing states.

A team had reviewed files to determine that roughly 1,000 files linked to by that account out of 300,000 available matched non-public evidence provided.

“The fact that the file folder names and folder structure on the webpage significantly match the non-public names and file structure of the materials produced in discovery, and the fact that over 1,000 files on the webpage match those produced in discovery, establish that the person(s) who created the webpage had access to at least some of the non-sensitive discovery produced by the government in this case,“ the filing states.

Concord Management was among 13 Russian entities or people to be charged in connection with Mr Mueller's investigation last February.

Mr Mueller’s team has charged dozens of Russian individuals or entities for attempting to influence the 2016 presidential election, primarily through hacking Democratic Party email systems.

The most recent filing argued that attorneys for Concord should not be given access to “sensitive” evidence gathered for the case.

It said: “The person who created the webpage used their knowledge of the non-sensitive discovery to make it appear as though the irrelevant files contained on the webpage were the sum total evidence of ‘IRA and Russian collusion’ gathered by law enforcement in this matter in an apparent effort to discredit the investigation."