U.S. intelligence agencies and the Department of Homeland Security are not seeing evidence so far of a concerted effort by Russia to hack or penetrate American election systems during the 2018 midterms, top Homeland Security officials told lawmakers Wednesday.

Although the 2018 “midterms remain a potential target for Russian actors,” the intelligence community has yet to see evidence of a robust campaign aimed at tampering with our election infrastructure along the lines of 2016 or influencing the makeup of the House or Senate races, Christopher Krebs, the top DHS official overseeing cybersecurity and elections security, told the House Homeland Security Committee.

But intelligence agencies do see Russian actors using social media platforms, adopting false personas and other means to inflame Americans on controversial issues, Krebs said.

Across the Capitol in a Senate Rules Committee hearing on election security, Matthew Masterson, a cybersecurity adviser to the Department of Homeland Security, echoed Krebs’ comments. Krebs and Masterson deviated from their prepared remarks to emphasize that there wasn’t sufficient evidence of Russian efforts to target state election systems, as Moscow did during the 2016 presidential election.

U.S. officials have said that Russia attempted to break into as many as 21 state election systems during the 2016 presidential election and managed to access voter registration databases in a handful of cases, though no vote totals were altered as a result.

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While Director of National Intelligence Daniel Coats has also been raising the alarm on potential Russian interference in the midterms, he has toned down his remarks in recent weeks. In February, Coats told the Senate Intelligence Committee that Russia viewed its 2016 efforts as successful and Moscow “views the 2018 midterm U.S. elections as a potential target.” He told lawmakers, “Frankly, the United States is under attack.”

In June, at an event organized by the Atlantic Council, Coats said, “We continue to see Russian targeting of American society in ways that could affect our midterm elections.”

Democratic Rep. Bonnie Watson Coleman of New Jersey pressed Krebs on whether Russian actors attempting to penetrate election systems could be going undetected. Krebs responded, “I don’t know what I don’t know.”

Top Republican lawmakers on the House Homeland Security panel downplayed Russian threats to elections, saying that Moscow has been trying to influence American elections for a century.

“Russia, or the USSR in its previous version, has been involved in the United States and undermining the United States since 1917, since the Bolshevik revolution,” Republican Rep. Scott Perry of Pennsylvania said. “They infiltrated our government at the very highest levels and influenced policy in magnificent effect in the decades past. … So this is nothing new.”

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Rep. Michael McCaul of Texas, chairman of the House Homeland Security Committee, echoed Perry’s view, saying that “foreign adversaries influencing our elections has been going on for quite some time, but now they have found a new tool” in the form of cyber capabilities.

McCaul cited an example from the 1990s when a Chinese foreign national was charged with contributing money to President Bill Clinton’s campaign.

Over in the Senate Rules Committee, meanwhile, Republican lawmakers pressed witnesses on whether Russian interference in the 2016 election led to any alteration of vote totals.

GOP Sen. Ted Cruz of Texas said no vote totals were altered in 2016 and that most of the Russian efforts aimed at local elections systems were at an elementary level of simple probing and scans — something that happens to computer systems all around the world every day.

Christy McCormick, vice chairwoman of the Election Assistance Commission, told Cruz it “would be very difficult” for a foreign entity to alter vote totals. There are 8,000 voting jurisdictions in the United States, none of them connected electronically to each other, and election officials are vigilant about checking machines before and after elections for any tampering, she said.

Still, she said, “Every system is vulnerable and things can happen. … It would be difficult, but I can’t ever say impossible.”

Such assurances left Democratic Sen. Mark Warner of Virginia, who also is a member of the Senate Intelligence Committee, worried.

“I am very concerned that there is a lot of chest thumping about how well we did in 2016, and I think we should be very cautious in terms of some of those claims made, especially as we face an ongoing threat,” Warner told the Senate Rules Committee. “Russia and or others will be back in trying to penetrate our systems. … I’m afraid some of these self-accolades could come back to bite us.”