Story highlights

Sources confirmed the Senate and House intelligence committees had been briefed on the hack

While the US has not publicly named Russia as the culprit, the White House says it is the belief of experts

Washington CNN  — 

Amid reports that the hack of the Democratic National Committee was even broader than had been made public, the highest-ranking Democrat in Congress is calling the incident an “electronic Watergate.”

Speaking to reporters on Thursday, House Minority Leader Nancy Pelosi compared the hack to the infamous break-in of DNC offices at the Watergate complex that was tied back to President Richard Nixon and the White House.

“Let me just say this in terms of the presidential campaign: This is an electronic Watergate,” Pelosi said. “This is a break in.”

Pelosi was responding to a report late Wednesday by The New York Times that the scope of the hack of the DNC was broader than had been known. Citing sources familiar with the investigation, the Times reported that hackers compromised the private email accounts of over 100 party officials and groups, including officials in the campaign of Hillary Clinton and the Democratic Governors Association – though a Democratic source said that the DGA inclusion was incorrect.

The cyberattacks did include a breach of private email accounts of a number of Democratic party officials, some with direct ties to the Clinton campaign, a US official familiar with the investigation confirmed to CNN. The official said investigators believe they now have a sense of how wide the attack reached.

The Clinton campaign has not been told by the FBI that their data was affected, according to an aide. The campaign has met with the FBI about the hack, though, the aide said, and the FBI told them phishing attempts had been directed at the campaign. The campaign said it had been aware of those attempts.

Also on Thursday, sources confirmed the Senate and House intelligence committees had been briefed on the matter. Neither revealed details of the contents of the meeting.

According to a Democratic source familiar with the hack, the DNC’s analytics platform was compromised and data with the Clinton campaign along with it, but data from the DGA was not affected. The DGA recently began using the platform that tracks field operations, while the Clinton campaign has used it throughout the primary process, the source said.

The hack was originally discovered as being two separate breaches of the DNC, both by hacking groups identified by cybersecurity experts as working for the Russian military and intelligence complex. One hack was said to have lasted a year and targeted internal communications, the other was for a few months and targeted opposition research on Donald Trump.

The DNC email scandal explained

Federal investigators had tried to warn the DNC months before, sources told CNN, but by the time the suspected Russian hackers were kicked out of the systems damage had been done: Nearly 20,000 emails between a handful of DNC officials were dumped on the web by Wikileaks as the Democratic National Convention was kicking off. The emails showing opposition to Vermont Sen. Bernie Sanders during the primary led to the resignation of DNC Chairwoman Debbie Wasserman Scultz on the eve of the convention and departure of more party officials later.

While the US has not publicly named Russia as the culprit, the White House has acknowledged that is the belief of experts who investigated the cyberattack. Pelosi said Thursday she knows “for sure it is the Russians,” though she didn’t know if the attack affected the DGA.

DNC hack: What you need to know

It was previously reported that a staffer researching Trump campaign Chairman Paul Manfort’s ties to Russia and the Ukraine was notified by Yahoo that her personal email account had been targeted by nation-state hackers.

“I think that we have to recognize what is happening here,” Pelosi said Thursday. “The Russians broke in. Who did they give the information to? I don’t know. Who dumped it? I don’t know. But I do know that this is a Watergate-like electronic break in. And anyone who would exploit for the purpose of embarrassment or something like that is an accomplice to that.”

Experts believe Russia is behind the release of information from the hack online in an effort to influence the presidential election.

House Intelligence ranking member Adam Schiff on Thursday said his committee had been briefed on “reported hacking into different Democratic campaign organizations,” but could not go further on who was behind it.

He renewed a call on the White House to make its evidence on attributing the hack public.

“If this indeed turns out to be a cyberattack and leak conducted by a foreign actor to influence our elections, that would be a grave matter that should come with serious consequences,” Schiff said. “That foreign actors may be trying to influence our election – let alone a powerful adversary – should concern all Americans of any party.”

The DNC will begin notifying victims whose information was compromised in the breach and leak next week, according to a memo from DNC interim chairwoman Donna Brazile that was obtained by CNN.

She also announced the creation of a cybersecurity advisory board to the DNC that will include former DHS official Rand Beers, former White House CTO Aneesh Chopra, former deputy US CTO Nicole Wong and attorney and former prosecutor Michael Sussman.

CNN’s Deirdre Walsh, Shimon Prokupecz, Jeff Zeleny, Manu Raju and Dan Merica contributed to this report