A top Russian diplomat has criticized the U.S. of creating "unprecedented anti-Russian hysteria" when it publicly accused Russia of launching a series of cyber attacks that were aimed at undermining the upcoming U.S. elections.

"The supercharging of emotions about Russian hackers is being used in the pre-election fight. The current administration, taking part in this fight, is not averse to dirty methods," Deputy Foreign Minister Sergei Ryabkov said Saturday on the ministry's website.

Russia Says US Cyber-attack Claims Fan 'Anti-Russian' Sentiment

Late Friday, the U.S. administration stopped short of calling Russia's intrusions an act of cyberwar but said it is “confident” Russia directed the hacks of the Democratic National Committee in July, leaking thousands of emails that embarrassed the party in the days leading up to its national convention.

Russia Says US Cyber-attack Claims Fan 'Anti-Russian' Sentiment

“These thefts and disclosures are intended to interfere with the US election process,” according to the statement from the Office of the Director of National Intelligence and the Department of Homeland Security.

Russia Says US Cyber-attack Claims Fan 'Anti-Russian' Sentiment

“We believe, based on the scope and sensitivity of these efforts, that only Russia's senior-most officials could have authorized these activities,” the statement added.

For several weeks, intelligence officials said they suspected Russia of orchestrating the attacks, noting that Russia has used similar “tactics and techniques” to influence public opinion across Europe and Eurasia.

But U.S. intelligence community decided to go public with the attribution after newly uncovered information allowed them to reach a “higher degree of confidence,” one official told VOA.

The U.S. also said a series of recent cyber intrusions into state and local election-related systems originated from servers operated by a company in Russia, though it was not yet able to say whether those actions were also directed by Moscow.

“There’s an urgency here to release as much information as possible so the state and local authorities can fortify their [election] infrastructure,” a senior administration official told VOA on condition of anonymity. “We’re committed to making sure our election process is secure.”

At least 21 U.S. states have already sought cybersecurity assistance from the Department of Homeland Security, and officials are encouraging more state and local election officials to reach out.

Despite publicly naming Russia as the culprit behind the hacked emails released by Wikileaks and DCLeaks.com, U.S. officials do not expect the attacks to stop.

Instead, they expect Russia to continue with a stream of activity, enough to foment tensions but below the threshold that would trigger a severe escalation in hostilities.

The U.S. warned it will not sit idly by.

“Some responses you may see and others you may not,” a U.S. intelligence official cautioned.

But so far, the U.S. is leery of labeling the Russian cyberattacks as acts of war.

A senior administration official said even though the attacks targeted systems critical to the country’s democracy, it is “more useful” to look at each individual situation, and that a response could include diplomatic, economic or cyber actions.

“That full range of tools will be considered,” the official said. “That’s going to happen at the time and place of our choosing.”

National security expert Nicholas Rostow, a professor at the National Defense University, said he is not surprised that Russia is believed to be behind the hacks. While acknowledging that such a security breach is “a very bad thing,” he says “it’s hardly surprising in this day and age.” Russian President Vladimir Putin, he noted, is an intelligence specialist who spent years working for the KGB, Russia’s intelligence agency.

Rostow said he would not classify the U.S. statement as an act of war, but rather one more incident in a long session of “cyber struggle” with Russia. He said he “would be surprised if Russia is the only one trying to interfere,” noting that the United States also has a contentious relationship with China, and with Cuba. “There’s a constant effort to get at each other’s computers, to defend the computers, the communications, and all the rest of it,” he said.

Meanwhile, U.S. officials are trying to reassure voters that they system is safe. They say the hacks are meant to undermine confidence in the voting system.

"What people need to know about this is that our voting infrastructure is really quite resilient," Homeland Security Adviser Lisa Monaco told a Cyber Warfare Summit hosted by the Washington Post on Thursday. "We ought to be very confident in our election system."