The FBI confirmed in a statement Monday that a professional cybercriminal group called DarkSide was responsible for a ransomware attack on the Colonial Pipeline network, which provides roughly 45% of the fuel used on the East Coast.

The latest: President Biden said at a press briefing that there is no evidence so far to indicate that Russia was involved in the attack, although he plans to meet with Russian President Vladimir Putin soon. Officials previously said no countries are being blamed for the attack.

Colonial said in a statement at 12:25pm ET on Monday that segments of the pipeline are being brought back online in a "stepwise fashion," with the goal of "substantially restoring operational service by the end of the week."

• White House officials said at a press briefing that the FBI has been investigating the DarkSide ransomware since October of last year.
• "It's a ransomware as a service variant, where criminal affiliates conduct attacks and then share the proceeds with the ransomware developers," deputy national security adviser Anne Neuberger said.

Worth noting: Neuberger would not answer whether Colonial has paid a ransom, telling reporters that they are a private company and that the White House will defer those "very difficult" decisions to them. She added that the administration has not offered Colonial any further advice.

The big picture: Colonial is the largest refined fuel pipeline network in the country, transporting over 100 million gallons per day. It has been out of operation since Friday as a result of the hack, raising fears of a surge in fuel prices.

• The FBI said it would continue to work closely with Colonial and government partners on the investigation. "Right now, there is not a supply shortage," said White House homeland security adviser Elizabeth Sherwood-Randall.
• Energy analyst Amy Myers Jaffe told Politico that the hack is "the most significant, successful attack on energy infrastructure we know of in the United States."

What they're saying: DarkSide posted the following statement to its website on Monday, according to CNBC: