US intelligence and law enforcement agencies are probing what they see as a broad covert Russian operation in America to sow public distrust in the upcoming presidential election and in US political institutions, intelligence and congressional officials said.

The aim is to understand the scope and intent of the Russian campaign, which incorporates cyber-tools to hack systems used in the political process, enhancing Russia's ability to spread disinformation.

The effort to better understand Russia's covert influence operations is being spearheaded by James Clapper, the director of national intelligence. "This is something of concern for the DNI," said Charles Allen, a former long time CIA officer who has been briefed on some of these issues. "It is being addressed."

A Russian influence operation in the United States "is something we're looking very closely at," said one senior intelligence official. Officials are also examining potential disruptions to the election process, and the FBI has alerted state and local officials to potential cyber-threats.


The official cautioned that the intelligence community is not saying it has "definitive proof" of such tampering, or any Russian plans to do so. "But even the hint of something impacting the security of our election system would be of significant concern," the official said. "It's the key to our democracy, that people have confidence in the election system."

The Kremlin's intent may not be to sway the election in one direction or another, officials said, but to cause chaos and provide propaganda fodder to attack US democracy-building policies around the world, particularly in the countries of the former Soviet Union.

US intelligence officials described the covert influence campaign here as "ambitious" and said it is also designed to counter US leadership and influence in international affairs.

One congressional official, who has been briefed recently on the matter, said "Russian 'active measures' or covert influence or manipulation efforts, whether it's in Eastern Europe or in the United States" are of concern.

It "seems to be a global campaign," the aide said. As a result, the issue has "moved up as a priority" for the intelligence agencies, which include the FBI and Department of Homeland Security as well as the CIA and the National Security Agency.

Some congressional leaders briefed recently by the intelligence agencies on Russian influence operations in Europe, and how they may serve as a template for activities here, have been disturbed by what they heard.

After Senate Minority Leader Harry Reid ended a secure, 30-minute phone briefing by a top intelligence official recently, he was "deeply shaken," according to an aide who was with Reid when he left the secure room at the FBI's Las Vegas headquarters.

The Russian government hack of the Democratic National Committee, disclosed by the DNC in June but not yet officially ascribed by the US Government to Russia, and the subsequent release of 20,000 hacked DNC emails by WikiLeaks, shocked officials. Cyber-analysts traced its digital markings to known Russian government hacking groups.

"We've seen an unprecedented intrusion and an attempt to influence or disrupt our political process," said Congressman Adam Schiff, the ranking Democrat of the House Intelligence Committee, speaking about the DNC hack and the WikiLeaks release on the eve of the Democratic convention. The disclosures, which included a number of embarrassing internal emails, forced the resignation of DNC Chairwoman Debbie Wasserman Schultz.

Members of both parties are urging President Barack Obama to take the Russians to task publicly.

Administration officials said they are still weighing their response.

Russia has denied that it carried out any cyber-intrusions in the United States. President Vladimir Putin called the accusations against Russia by US officials and politicians an attempt to "distract the public's attention".

"It doesn't really matter who hacked this data from Mrs Clinton's campaign headquarters," Putin said, referring to Democratic presidential nominee Hillary Clinton, in an interview with Bloomberg. "The important thing is the content was given to the public."

The Department of Homeland Security has offered local and state election officials help to prevent or deal with Election Day cyber-disruptions, including vulnerability scans, regular actionable information and alerts, and access to other tools for improving cyber-security at the local level. It will also have a cyber-team ready at the National Cyber-security and Communications Integration Centre to alert jurisdictions if attacks are detected.

Last month, the FBI issued an unprecedented warning to state election officials urging them to be on the lookout for intrusions into their election systems and to take steps to upgrade security measures across the voting process, including voter registration, voter roles and election-related websites. The confidential "flash" alert said investigators had detected attempts to penetrate election systems in several states.

Arizona, Illinois and both the Democratic and Republican parties, as well as the DNC, have been the victims of either attempted or successful cyber-attacks that FBI agents with expertise in Russian government hacking are investigating.