Deputy Attorney General Rod Rosenstein announced new indictments Friday in special counsel Robert Mueller's investigation into Russia's interference during the 2016 presidential campaign.

Twelve Russian intelligence officers have been indicted for allegedly hacking the Democratic National Committee, the Democratic Congressional Campaign Committee and Hillary Clinton's campaign, and releasing emails under the names DC Leaks and Guccifer 2.0, with the intention of impacting the results of the 2016 presidential campaign.

The officers named in the indictment are members of a Russian military intelligence agency called the Main Intelligence Directorate of the General Staff, commonly referred to as the GRU.

"There is no allegation in this indictment that any American citizen committed a crime," Rosenstein said during a press conference at the Department of Justice on Friday. "There is no allegation that the conspiracy altered the vote count or changed any election result."

Though no Americans were named in Friday's indictments, the suspects used the Guccifer 2.0 persona to communicate with "senior members" of President Trump's presidential campaign, according to court filings. They also communicated and sent stolen documents to "a candidate for the U.S. Congress," a "then-registered state lobbyist," and an unnamed reporter.

Former New York City mayor Rudy Giuliani, who is part of Trump's legal team, used the fact that no Americans were named in the indictment to call on Mueller to end his investigation into Russian meddling.

The indictments come just days before Trump is scheduled to meet with Russian President Vladimir Putin during a summit in Helsinki, Finland. That meeting is scheduled for Monday. Rosenstein told reporters that the timing of the announcement of the indictment had nothing to do with the upcoming summit, and that he had briefed Trump on this latest round of indictments earlier this week.

That didn't prevent Trump from once again referring to Mueller's investigation as a "rigged witch hunt" during a press conference with British Prime Minister Theresa May Friday morning.

Sen. Chuck Schumer (D., N.Y.) issued a statement calling on Trump to cancel his upcoming meeting with Putin until Russia takes "demonstrable and transparent steps" to prove it wouldn't interfere in future elections, including the upcoming midterms.

"Glad-handing with Vladimir Putin on the heels of these indictments would be an insult to our democracy," Schumer said in the statement.

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The indictments undermine claims from Wikileaks founder Julian Assange that there were no links between the Russian government and the hacked documents. They also further debunk conspiracy theories, pushed by Trump supporters such as Fox News host Sean Hannity, that suggested slain DNC staffer Seth Rich was behind the leaked emails.

"It's somewhat surprising Wikileaks wasn't indicted," CNN senior legal analyst Jeffrey Toobin said following the press conference.

Prior to Friday's announcement, Mueller's investigation into Russian meddling during the 2016 presidential campaign had led to indictments or guilty pleas for at least 20 individuals and three companies.

In the most high-profile case related to Mueller's investigation, Paul Manafort, Trump's former campaign chairman, was indicted in October on a host of charges, including conspiracy, money laundering and making false statements to the FBI. On Thursday, Manafort was moved to a jail in Alexandria, Va., to await his criminal trial, which is scheduled to begin later this month.

Additionally, former National Security Adviser Michael Flynn and Trump campaign adviser George Papadopoulos have pleaded guilty to making false statements to the FBI about the contacts they had during the campaign with Russians. Rick Gates, another Trump campaign aide, pleaded guilty to lying to investigators and one conspiracy charge.

Thirteen Russian nationals and three Russian companies have also been indicted on conspiracy charges related to the Kremlin's efforts to undermine the results of the 2016 election with false propaganda distributed on Facebook and other social media platforms.

Mueller's investigation has also secured other guilty pleas. Richard Pinedo pleaded guilty to identify fraud in connection with the Russian indictments, and London attorney Alex van der Zwaan pleaded guilty to making false statements to the FBI involving Gates. van der Zwaan served 30 days in a low-security Federal Bureau of Prisons facility near Allenwood, Pa.