Special counsel Robert Mueller indicted Russian intelligence operatives for the 2016 election interference to sabotage President Trump’s upcoming summit with Russian President Vladimir Putin, according to Russian diplomats.

[READ HERE: Mueller's indictment against 12 Russians for hacking Democrats in 2016]

"Obviously, the goal of this 'mud-slinging' is to spoil the atmosphere before the Russian-American summit,” the Russian Foreign Ministry said Friday, per Sputnik, a state-run media outlet.

Mueller, a former FBI director, accused 12 Russian military intelligence officers of conducting a cyber espionage campaign to steal and publish internal Democratic party emails throughout the 2016 election season. The Russian government conducted the cyberattacks to “stage releases of the stolen documents to interfere with the 2016 U.S. presidential election,” the court documents say.

“The timing is a function of the collection of the facts, the evidence, the law and a determination that it was sufficient to present the indictment at this time,” Deputy Attorney General Rod Rosenstein, a Trump appointee who established the Mueller probe after Attorney General Jeff Sessions recused himself from the Russia investigation, said Friday.

Russian officials have denied any involvement and called Mueller’s latest indictment a “shameful farce.” But it marked the most detailed Justice Department account of how emails were stolen from the Democratic Party — as well as Hillary Clinton’s campaign chairman, John Podesta — and released to the media.

“[The Russian officers] targeted their victims using a technique known as spear phishing to steal victims’ passwords or otherwise gain access to their computers,” the indictment alleges. “Beginning by at least March 2016, the conspirators targeted over 300 individuals affiliated with the Clinton Campaign, [the Democratic Congressional Campaign Committee], and [the Democratic National Committee].”

Russian officials have described the election interference controversy as a scam designed to sabotage U.S.-Russia relations.

“Now influential political forces in the United States, which are against normalization of relations between our countries and for two years have been indulging in vilifying Russia, are trying to get the most out of yet another fake matter that will be forgotten very soon,” the Foreign Ministry said in TASS, another state-run outlet.

President Trump also has complained that the controversy has constrained his diplomatic options with respect to Russia.

“We have stupidity going on in the U.S. that makes it hard to do something with Russia,” he said during a joint press conference with British Prime Minister Theresa May, hours before Rosenstein unveiled the new indictment. “People say, 'He loves Russia' — I love the U.S.”

But the president also argued that his criticism of NATO allies who fail to meet their defense spending obligations shows his willingness to take a tough line on Russia. “We had people who weren't paying their bills or following commitments,” he said. “When you look at what we've done in terms of Russia, I bet they're saying, 'I wish Trump wasn't the victor in that election.’”

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