Mueller previously charged Manafort in two separate lawsuits with conspiring to launder money, lying to investigators, committing tax and bank fraud, and failing to register as a foreign agent.
The witnesses worked with Manafort in organizing a group of former European officials who lobbied within the US without registering as required by law. It also marked the first time Kilimnik, who in previous court filings was referred to only as "Person A" and described as having links to Russian spy agencies, was named.
The indictment charges that former Ukraine president Viktor Yanukovych and his political party retained lobbyists through Manafort to serve as intermediaries with the former European politicians.
Perhaps more important is that an alleged line from the Russian government to the Trump campaign could be getting clearer. The case ratchets up pressure on President Trump's former campaign chairman as he tries to stay out of jail while awaiting trial, reports the Washington Post.
She reportedly was said to have damaging information on Trump's campaign rival, Hillary Clinton, which was "part of Russian Federation and its government's support for Mr. Trump".
"Mr. Manafort asked no one to provide a false affidavit or false testimony at trial, or perjure themselves, and he has not given - nor offered to give - any potential witness anything in exchange for false testimony", the response said. Gates has already pleaded guilty and is cooperating with Mueller's investigation.
"Mr. Manafort is innocent and nothing about this latest allegation changes our defense", Manafort spokesperson Jason Maloni told ABC News in a statement on Tuesday.
Gates reached a plea deal in February and agreed to cooperate with the special counsel investigation. Among the alleged texts Mueller highlighted was one in which Kilimnik told one associate that Manafort wanted to "give him a quick summary that he says to everybody (which is true) that our friends never lobbied in the USA, and the objective of the program was European Union".
Manafort is now out on house arrest and a $10 million unsecured bail.
They said Manafort's "limited communications can not be fairly read, either factually or legally, to reflect an intent to corruptly influence a trial witness". The judge demanded to see the memo because the charges brought against Manafort are well outside the scope of the Russian Federation probe.
It was the third time Mueller had added to charges against Manafort since he was indicted in October. No meeting took place, the people said, and Deripaska has said he had no communications or interactions with Manafort during or after the presidential campaign.
After working in Moscow as an interpreter for the International Republican Institute, a Washington-based organization, he helped Manafort lobby for pro-Russian politicians in Ukraine.