WASHINGTON — Special Counsel Robert Mueller on Friday secured the indictment of 13 Russian nationals and three entities on charges related to attempts to interfere in the 2016 presidential election.

Also named in the 37-page indictment were the Internet Research Agency and two other entities, in what is described as a concerted effort to undermine the election and conduct “information warfare” against the United States.

The efforts included efforts to support Donald Trump and to sow discord about Hillary Clinton . That included creating fake social media accounts on Facebook and Twitter, in some cases using stolen identities and posing as “politically active” Americans. They also purchased ads on social media networks and paid real Americans to participate, and staged rallies to support Trump.

The indictments were the first filed by Mueller that charge specific individuals with interference in the election.

In a press conference, Deputy Attorney General Rod Rosenstein said that “there is no allegation in the indictment that any American was a knowing participant in the alleged unlawful activity. There is no allegation in the indictment that the charged conduct altered the outcome of the 2016 election.”

He said that the investigation of Mueller’s investigation is ongoing. The special counsel is also investigating whether there was any coordination between Russian interests and the Trump campaign.

A federal grand jury returned the indictment on Friday. The defendants were charged with conspiracy to defraud the United States. Three of the defendants were charged with conspiracy to commit wire fraud and bank fraud, and five defendants with aggravated identity theft.

According to the indictment, some of the defendants “posing as U.S. persons without revealing their Russian association, communicated with unwitting individuals associated with the Trump campaign and with other political activists to seek to coordinate political activities.”

The indictment is here.

A dozen of the defendants named in the indictment worked for the Internet Research Agency, which is based in St. Petersburg, Russia and already has been identified as the entity behind some of the fake social media campaigns and propaganda efforts. The indictment claims that the other individual defendant,  Yevgeniy Viktorovich Prigozhin, funded the conspiracy through entities called Concord Management and Consulting LLC, and Concord Catering.

Rosenstein said the Russian conspiracy was part of an effort called Project Lakhta, and, through the Internet Research Agency, employed hundreds of people in its online operations, with an annual budget of “millions of dollars,” he said. The effort began in 2014.

The Justice Department alleges that the Russian interests bought space on computer servers in the U.S. and set up a “virtual private network.” They then used that capacity to set up Facebook, Instagram and Twitter accounts to make it look like they were American in origin.

“The Russians also recruited and paid real Americans to engage in political activities, promote political campaigns and stage political rallies,” Rosenstein said. He said that the Americans “did not know that they were communicating with Russians.”

In one instance cited in the indictment, the Russians contacted with a “real U.S. person affiliated with a Texas-based grassroots organization.” The person told them that they should focus their attention on “purple states like Colorado, Virginia and Florida.” After that, the defendants “commonly referred to targeting ‘purple states’ in directing their efforts.”

In another instance, according to the indictment, the defendants paid unidentified real U.S. citizens to perform tasks at rallies, including one person who built a cage on a flatbed truck and another person who wore a costume as Clinton in a prison uniform.

Although some of the staged events cited in the indictment were pro-Trump and anti-Clinton, Rosenstein said that after the election, “the defendants organized one rally to support the president-elect and another rally to oppose him—both in New York, on the same day.”