March 30 (UPI) -- Hearings before the Senate Intelligence Committee revealed Thursday that Democrats were not the only ones targeted by Russian hackers -- Republican Sen. Marco Rubio's campaign was also targeted twice, the former candidate and committee member acknowledged.
The matter was raised by Clinton Watts, a cybersecurity expert and fellow at the Foreign Policy Research Institute who was briefing the committee on the background of the issue. He singled out Rubio as an example of how Russian efforts to influence the outcome of the election stretched back into the primaries.
"Russia's overt media outlets sought to sideline opponents on both sides of the political spectrum," Watts said. "Senator Rubio, in my opinion, you suffered through these efforts."
Rubio did not immediately address the comment during the hearing, but later said members of his campaign staff who had access to internal campaign data and deliberations were the target of Internet-based cyberattacks in the summer of 2016 from IP addresses inside Russia. A second attempt was made Wednesday against former members of Rubio's campaign team, the senator said.
Rubio said the hackers were not successful and gained no information. The first attempt happened after he had already dropped out of the presidential race and decided to seek re-election to the Senate.
Watts went on to say Rubio and House Speaker Paul Ryan -- two Republicans who have at times clashed with President Donald Trump -- are still the target of active social media smear campaigns created by the Russians.
Sen. Lindsey Graham, R-S.C., another former presidential candidate and one of Trump's most vocal critics within the GOP, has previously said his campaign was targeted for Russian hacking, as well.
The Rubio revelation came as multiple experts told the Senate Intelligence Committee that they tend to agree with the U.S. intelligence community's assertion that Russia's government played an active role in interfering in the 2016 U.S. presidential election.
Thursday marked the panel's first open hearings into the investigation about potential Kremlin efforts on behalf of Trump. At no point in Thursday's initial hearings did witnesses suggest there is evidence the Trump campaign colluded with the Russians. The Russian cyberattack, however, most clearly targeted Hillary Clinton and the Democrats. At several crucial points in the campaign, information gleaned by Russian hacking of the Democratic National Committee and Clinton's campaign chairman John Podesta was leaked, creating embarrassing headaches for the Democrats.
The intelligence community -- including the CIA -- concluded weeks ago that Moscow was behind concerted efforts to intercede in the presidential election with, at the very least, tacit approval from Russian President Vladimir Putin.
"They have a history of doing this well before this and they find it a successful use of their resources," Roy Godson, a former consultant for the National Security Council, told the committee. He also told the panel that Moscow likely began laying the groundwork for their interference efforts long before 2016.
"They will be relying on all tools in their toolkit. And information warfare and disinformation will be part of it," Eugene Rumer, director of the Russia and Eurasia Program at the Carnegie Endowment for International Peace, said.
Panel members and witnesses spent time during Thursday morning's hearing talking about whether Moscow hacking into foreign governments constitutes an act of war.
"It's not kinetic, but its definitely part of the Cold War system we knew," Watts said, adding that the Russians hit "a gold mine" when they hacked into Democratic National Committee emails last year.
"I think we should be careful of using terms of an 'act of war,'" Rumer said.
There is currently no formal definition of what types of cyberattacks warrant a military response.
Thursday's hearing began after the committee's chair and vice chair, Sens. Richard Burr, R-N.C., and Mark Warner, D-Va., again stressed the bipartisan spirit of their investigation, much as they had on Wednesday.
"If we politicize this process, our efforts will likely fail," Burr said at the start of the hearing.
The panel was set for two hearings on Thursday, one in the morning and one in the afternoon. It is running concurrent to the House Intelligence Committee's probe of the same matter. Burr and Warner took pains earlier this week to distance themselves from the House investigation being led by Rep. David Nunes, who has come under fire from Democrats for appearing to aid the Trump administration.
The FBI is also conducting its own independent investigation into Russia's role influencing the outcome of the election. FBI Director James Comey briefed lawmakers about the general direction of that investigation on Monday, the first time he publicly acknowledged the widely reported probe.