Jeh Johnson, the former secretary of homeland security. Aaron P. Bernstein/Reuters Current and former officials said in testimony before the congressional intelligence committees on Wednesday that Russian hackers infiltrated election systems in at least 21 states leading up to Election Day in a "well-planned, well-coordinated" campaign directed by Russian President Vladimir Putin.

The overlapping House and Senate hearings were held amid questions about President Donald Trump's stance on Russia's election interference and whether he believes it occurred at all.

Former FBI Director James Comey told the Senate Intelligence Committee earlier this month that Trump asked about the Russia investigation only with regard to how it affected him personally rather than how it affected US national security. And The New York Times reported that Trump — who has called the investigation a "fake" attempt by Democrats to justify their defeat — was questioning whether Russia was behind the hacks as late as March in conversations with intelligence chiefs.

White House press secretary Sean Spicer did not provide a definitive answer Tuesday when asked whether Trump believed Russia interfered in the election, telling reporters that he had not "sat down" with Trump and asked him about it since he took office five months ago.

There were many questions the witnesses — including former Homeland Security Secretary Jeh Johnson and one of the FBI's top counterintelligence officials, Bill Priestap — could not answer because of restrictions on disclosing classified information in an open setting. But they were unequivocal on one point: Americans should have no doubt that Russia meddled in the election.

When asked how the intelligence community had determined Russia was behind the hacks, Johnson told the House Intelligence Committee that he could not get into specifics because it would require describing sensitive sources and methods. But he said the intelligence he saw showed that Moscow was responsible "beyond a reasonable doubt." He also pointed to Putin as the person who had ordered the meddling.

At the Senate committee hearing, Democratic Sen. Joe Manchin asked Priestap and DHS officials Sam Liles and Jeanette Manfra whether there was "an American right now who should have a reasonable doubt" that Russia interfered. They all replied that there was no reason to doubt that conclusion.

Priestap told the committee that Russia had conducted operations targeting US elections "for years," but that none had been equal to its efforts in 2016.

"The scale and aggressiveness" of the interference "made this time different," Priestap said.

At least 21 states targeted

Manfra, a top official in the DHS's National Protection and Programs Directorate, said Russian hackers targeted election systems in at least 21 states last year. The hackers probed election infrastructure and successfully infiltrated a "small number of networks," said Liles, the DHS's top cyber official.

The hackers stole voter-data information, which they could then use "in a variety of ways," Priestap said, including to affect future elections, target individual voters, and determine whether the data is something they can manipulate going forward.

Bloomberg reported last week that as many as 39 states were targeted. But Illinois and Arizona are the only states so far to have publicly confirmed their voter systems were attacked. That has frustrated Sen. Mark Warner, the vice chairman of the Senate Intelligence Committee, who has been pushing for DHS to make public a list of targeted states.

"How are we made safer by keeping the identity of those states a secret from the public?" Warner said.

In Illinois, the Russians appeared to be rummaging for sensitive information on voters. Hackers gained access to the state's voter database, which contained information such as the names, birthdates, driver's licenses, and partial Social Security numbers of 15 million people, according to Bloomberg.

And according to a top-secret National Security Agency document leaked to the Intercept and published earlier this month, hackers associated with Russia's military intelligence agency targeted a company with information on US voting software days before the election and used the data to launch "voter-registration-themed" cyberattacks on local government officials.

Johnson told the House committee that states' election systems were "very vulnerable" and that was why he pushed to designate them as critical infrastructure during the election. States were initially wary of accepting federal help in fending off cyberattacks but corralled around the DHS as Election Day grew closer.

"This is not just an academic exercise," Johnson said. "This is a very real threat."

Alex Halderman, a professor of computer science and engineering at the University of Michigan, put it bluntly.

"I know America's voting systems are vulnerable because my colleagues and I have hacked them," he told the Senate committee. "Repeatedly."