The U.S. Justice Department has charged a dozen Russian intelligence officers with a series of hacking offenses against the Democratic National Committee (DNC).

Deputy Attorney General Rod Rosenstein announced the indictments on Friday as part of the ongoing investigation into Russia’s possible interference with the 2016 presidential election.

The indictment accuses the Russian intelligence officers of hacking into the computer networks of the DNC and the Democratic Congressional Campaign Committee (DCCC), as well as the Clinton presidential campaign.

In addition, two defendants were charged with “conspiring to infiltrate computers of organizations responsible for administering elections, including state boards of election, secretaries of state, and companies that supply software and other technology used to administer elections,” Rosenstein said in a press conference.

According to the indictment, the hacking incidents date back to at least March 2016.

“The internet allows foreign adversaries to attack Americans in new and unexpected ways,” said Rosenstein.

“Free and fair elections are hard-fought and contentious and there will always be adversaries who work to exacerbate domestic differences and try to confuse, divide and conquer us,” Rosenstein said.

In February, the U.S. Justice Department indicted 13 Russian nationals and three Russian groups, including the Internet Research Agency, linked to propaganda efforts across social media during the 2016 election.

The announcement comes just days before President Trump’s plans to meet with President Vladimir V. Putin of Russia.

Russia has previously denied allegations of government involvement in cyber-attacks to influence the U.S. election results.