A dozen Russian intelligence officers have been charged with conspiring to hack Democrats during the 2016 presidential campaign.

The charges are the first from special counsel Robert Mueller’s office which directly accuse the Russian government of meddling in the presidential election.

According to the charges, released on Saturday (Friday afternoon local time), 12 members of Russian military intelligence, known as the GRU, allegedly engaged in a sustained effort to hack the computer networks of Democratic organisations and Hillary Clinton’s campaign.

The charges come just days before US President Donald Trump is due to meet his Russian counterpart, President Vladimir Putin in Helsinki, Finland, in a one-on-one private meeting with only interpreters present.

Deputy Attorney General Rod Rosenstein announced the charges at a press conference in Washington DC. They include 11 counts of conspiracy by Russian intelligence officials against the United States, money laundering and attempts to break into government agencies and state election boards.

U.S. Deputy Attorney General Rod Rosenstein (C) announces the charges against 12 Russian intelligence officers. Photo: Getty

Russia has denied that its government had any role in the hacking during the 2016 presidential campaign.

The indictment spells out in great detail the sustained effort to hack Democratic political operations, which began on March 19, 2016.

It included the implanting of hundreds of malware files on the Democrats’ computers before information was stolen and traded through fake personas including “DC Leaks” and “Guccifer 2.0”.

Russian intelligence officials sent personalised scam emails – an act described as “spear phishing” – in order to obtain sensitive information.

“The conspirators spearphished individuals affiliated with the Clinton Campaign throughout the summer of 2016,” the indictment reads.

The update to the Russia investigation comes as US President Donald Trump makes an official visit to Britain. Photo: Getty

“For example, on or about July 27, 2016, the Conspirators attempted after hours to spearphish for the first time email accounts at a domain hosted by a third-party provider and used by Clinton’s personal office.

“At or around the same time, they also targeted seventy-six email addresses at the domain for the Clinton Campaign.”

Since May 2017, special counsel Robert Mueller and a team of prosecutors have been working to determine whether any associates of the Trump campaign conspired with the Russian government to determine the outcome of the 2016 presidential election.

“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,” Mr Rosenstein said in a statement.

“So long as we are united in our commitment to the shared values enshrined in the Constitution, they will not succeed.”

The Russian agents are unlikely to ever be put on trial in the United States.

In July 2016, then-candidate Donald Trump encouraged Russia to hack Mrs Clinton’s emails and make them public. According to the indictment, Russian intelligence officials tried for the first time to break into the servers used by Mrs Clinton’s offices on that same day.

Democrats on Friday called for Mr Trump to cancel his meeting with Mr Putin. Senator Chuck Schumer of New York, the Democrat minority leader, said the meeting would be “an insult to our democracy”.

“These indictments are further proof of what everyone but the president seems to understand: President Putin is an adversary who interfered in our elections to help President Trump win,” he said in a statement on Friday.

But in his brief press conference, Mr Rosenstein maintained the charges did not involve any American citizens, including Mr Trump. The president’s lawyer also took to Twitter to defend Mr Trump while calling for an end to the Russia investigation.

The indictments Rod Rosenstein announced are good news for all Americans. The Russians are nailed. No Americans are involved. Time for Mueller to end this pursuit of the President and say President Trump is completely innocent.

— Rudy W. Giuliani (@RudyGiuliani) July 13, 2018

“The indictments Rod Rosenstein announced are good news for all Americans. The Russians are nailed,” Rudolph Giuliani wrote. “No Americans are involved. Time for Mueller to end this pursuit of the President and say President Trump is completely innocent.”

In London for talks with British Prime Minister Theresa May, Mr Trump claimed the investigation was hurting his ability to develop a close relationship with Mr Putin.

“I think that we’re being hurt very badly by the, I would call it the witch hunt; I would call it the rigged witch hunt,” Mr Trump said. “I think that really hurts our country and it really hurts our relationship with Russia.”

Ebony Bowden contributed reporting from New York City.