“This is probably going to be one of the most consequential cyberattacks in U.S. history,” one U.S. official said, after the National Security Council held its second meeting in three days about the attacks, which security experts have linked to Russian intelligence. “That’s the view from inside government — that we’re dealing with something of a scale that I don’t think we’ve had to deal with before.”

The breaches are also focusing new pressure on the executive branch’s Cybersecurity and Infrastructure Security Agency, which had already taken heat from President Donald Trump for refusing to support his election conspiracy theories. CISA, an arm of the Department of Homeland Security, has been without a permanent leader since Trump fired its widely respected director, Chris Krebs, in mid-November. And some government officials have already questioned whether it has the staffing and other resources to help the rest of the executive branch respond to such a sprawling attack.

DHS itself appears to have been one of the agencies the intruders breached, officials said Monday…

The intruders may have gained access to the email accounts as far back as June, POLITICO and other publications reported Sunday.