"It's unfortunate that it has taken over three weeks after the revelation of an intrusion this significant for this Administration to finally issue a tentative attribution," said Senator Mark Warner, vice chairman of the Senate Intelligence committee.
"I was thrown forward, knocked to the ground," officer Brenna Hosey told reporters about the moment of the explosion. "But I was able to catch myself, I was fine."
O'Brien "is holding NSC meetings tonight and tomorrow morning and will convene a high-level interagency meeting this week," National Security Council spokesman John Ullyot said.
US media reports said the FBI was investigating a group working for the Russian foreign intelligence service, SVR, and that breaches had been taking place for months.
Wray told lawmakers on Thursday he has not seen evidence of a "coordinated national voter fraud effort.
With all due respect to Director Wray, he has a hard time finding emails in his own FBI, let alone figuring out whether there's any kind of voter fraud.
The NSA and FBI said that Russia's Main Intelligence Directorate, known as the GRU, was using a hacking tool code named "Drovorub" to break into Linux-based computers.
Linux systems are used pervasively throughout National Security Systems, the Department of Defense, and the Defense Industrial Base - as well as the larger cybersecurity community writ large.