Special counsel Robert Mueller issued new charges Friday against former Trump campaign chairman Paul Manafort and a Russian-Ukrainian business partner accused of having ties to Russian intelligence agencies.

Mueller is charging Manafort and Konstantin Kilimnik with obstruction of justice and conspiracy to obstruct justice as part of an alleged scheme to force two witnesses in the case against Manafort to alter their testimony, according to the indictment.

The superseding indictment adds to the charges against Manafort, who is accused of conspiracy to launder money and failing to register as a foreign agent for his work for former Ukrainian President Viktor Yanukovych.

The new indictment, which was handed down in federal court in Washington, D.C., does not make any allegations about Manafort’s activities during the campaign. Mueller was initially tasked with investigation possible collusion between President Donald Trump’s campaign and the Russian government. So far, his investigation has focused heavily on Manafort’s pre-campaign consulting work.

The new indictment alleges that Manafort and Kilimnik attempted to influence witnesses between Feb. 23 and April 2018. (RELATED: Manafort Lawyers Say Mueller Unable To Produce Evidence Of Collusion)

The two individuals — referred to as Person D1 and Person D2 — first began working with Manafort and Kilimnik in 2012 as part of what Manafort referred to as “The Hapsburg Group.”

Persons D1 and D2 served as intermediaries to European politicians who Manafort paid to lobby secretly for Ukraine and Yanukovych.