Russians hacked or attempted to hack into election systems in 21 states, Department of Homeland Security officials confirmed to a Senate panel Wednesday, but stressed this didn’t affect any election outcomes.

“All the way through the Cold War up to our most recent election, in my opinion they have tried to influence all of our elections,” @FBI’s Priestap says.

However, federal officials would not disclose which states were victims of hacking attempts, other than Arizona and Illinois, which were revealed last year to have been attacked. State election officials, later testifying to the same panel, wanted more information from the federal government. Also, a top FBI official told the panel Russia has interfered in U.S. elections since the Cold War.

“We determined that internet-connected election-related networks in 21 states were potentially targeted by Russian government cyber actors. It is important to note that none of these systems were involved in vote tallying,” Samuel Liles, acting director of the cyber division for the DHS Office of Intelligence and Analysis, told the Senate Select Committee on Intelligence.

This was the latest in a series of Senate hearings regarding the continuing investigation into Russian interference into the 2016 presidential election. Former FBI Director James Comey and Attorney General Jeff Sessions both testified to the committee this month regarding the Russian probe.

“This vast majority of activity we’ve observed was indicative of simple scanning for vulnerabilities and analogous to someone walking down the street to see if you were home,” Liles said. “A small number of systems were unsuccessfully exploited as though someone rattled the door knob but was unable to get in, so to speak. Finally, a small number of the networks were successfully exploited. They made it through the door.”

During the hearing, the committee’s top Democrat, Sen. Mark Warner of Virginia, doggedly pressed the DHS and FBI and, if they were aware, state officials, to notify the public which states were targeted.

“I think there is a public obligation to disclose, again, not to relitigate 2016 but to make sure that we are prepared to for 2017, where I have state elections in my state this year, and 2018,” Warner said. “There are some in the political process that believe this whole Russian incursion into our elections is a witch hunt and fake news. I could very easily see some local elected official saying this is not a problem, this is not a bother.”

Liles returned to the point that Americans can have faith in the election, despite the cyber intrusions.

“Multiple checks and redundancies in U.S. election infrastructures, including diversity of systems, noninternet-connected voting machines, pre-election testing, and processes for media, campaign, and election officials to check, audit, and validate the results, all of these made it likely that cyber manipulation of the U.S. election system intended to change the outcome of the national election would be detected,” Liles said.

However, J. Alex Halderman, a professor of computer science and engineering at the University of Michigan, contended U.S. election equipment is “vulnerable to sabotage” that “could change votes.”

“We’ve found ways for hackers to sabotage machines and steal votes. These capabilities are certainly within reach for America’s enemies,” Halderman told senators.

He said he and his team spent 10 years researching cyber vulnerabilities of election equipment. The professor said:

Some say that the fact that voting machines aren’t directly connected to the internet makes them secure. But, unfortunately, this is not true. Voting machines are not as distant from the internet as they may seem. Before every election, they need to be programmed with races and candidates. That programming is created on a desktop computer, then transferred to voting machines. If Russia infiltrated these election management computers, it could have spread a vote-stealing attack to a vast number of machines. I don’t know how far Russia got or whether they managed to interfere with equipment on Election Day.

Sen. Roy Blunt, R-Mo., a member of the select committee, noted during the hearing the importance of preventing any manipulation of tallying votes.

“I would think that if you could get into the vote tallying system and you did want to impact the outcome of an election, obviously the vote tallying system is the place to do that,” Blunt said.

Blunt said he doesn’t want the federal government to take over elections, but does hope the DHS should “give advice to state and local election officials to be sure that that vote tallying system is protected at a level above other systems.”

Jeanette Manfra, the acting director of undersecretary at the DHS National Protection and Programs Directorate, insisted vote counting has a greater level of protection.

“What we can assess is that those vote tallying systems, whether it was the machines at a kiosk that a voter uses at a polling station or the systems that are used to tally votes were very difficult to access and particularly to access them remotely and then given the level of observation for vote tallying at every level of the process that adds into that we would have identified issues there, and there were no identified issues,” Manfra said.

Bill Priestap, the FBI’s assistant director of the Counterintelligence Division, said Russia “has for years conducted influence operations targeting our elections.” Though he said it was not equal to the interference in 2016.

Sen. Dianne Feinstein, D-Calif., seemed surprised Russia had interfered before and pressed him on details.

“The scale and the aggressiveness of the effort in my opinion made this one different,” Priestap told the senator. “Again, it’s because of the electronic infrastructure the internet, what have you today, that allowed Russia to do things that in the past they weren’t able to do.”

Citing previous intelligence reports, Priestap said Russia’s goal was to attempt to create discord and delegitimize the election. Citing those same reports, he said the interference was intended to harm Democrat Hillary Clinton and help then-Republican candidate Donald Trump.

Feinstein asked if Russians have ever taken sides in previous efforts. Priestap answered affirmatively, but couldn’t provide an immediate example.

“Yes, ma’am, they have. I’m sorry, I can’t think of an example off the top of my head, but all the way through the Cold War up to our most recent election, in my opinion they have tried to influence all of our elections since then,” Priestap said. “This is a common practice.”

One occurrence came ahead of the 1984 presidential race. A letter to then-Soviet General Secretary Yuri Andropov, dated May 14, 1983, KGB head Viktor Chebrikov explained that then-Sen. Ted Kennedy, D-Mass., was eager to “counter the militaristic policies” of President Ronald Reagan, and to undermine his prospects for re-election in 1984.

The National Association of Secretaries of State oppose the Department of Homeland Security designating election equipment as critical infrastructure, said Connie Lawson, the group’s president-elect and Indiana secretary of state.

“Threat sharing has been touted as a key justification for the designation,” Lawson told the senators. “Yet, nearly six months later, no secretary of state is currently authorized to receive classified threat information from our intelligence agencies. From information gaps to knowledge gaps that aren’t being addressed, this process threatens to erode public confidence in the election process as much any foreign cyber threat.”

The “critical infrastructure” designation puts locally-run elections under the same category as national defense, highways, the power grid, the food and water supply, and communications systems. The federal government can step in to protect these fronts in case of an emergency under the post-9/11 designation.

“It’s also shredding the rights that the states hold to determine their own election procedures, subject to the acts of Congress,” Lawson continued.

She added: “If I have one major request for you today—other than rescinding the critical infrastructure designation for elections—it is to help election officials get access to classified information sharing. We need this information to defend state elections from foreign interference and respond to threats.”