Biden says Colonial Pipeline is nearing ‘full operational capacity,’ and doesn’t rule out a counterattack.

President Biden on Thursday welcomed news that gas has begun flowing through a critical pipeline that was shut down by the company over the weekend after a ransomware attack by hackers, but he said that it will take time to resolve gas shortages along the East Coast and he warned stations not to engage in price gouging.

“They should be reaching full operational capacity as we speak, as I speak to you right now,” Mr. Biden said in remarks from the Roosevelt Room. “That is good news. But we want to be clear, we will not feel the effects at the pump immediately. This is not like flicking on a light switch.”

The president said he had “no comment” on reports that Colonial Pipeline had paid a $5 million ransom to a group of hackers based in Russia to restore operations on the 5,500-mile pipeline. But he said the United States will pursue “a measure to disrupt their ability to operate” against Darkside, the group behind the Colonial hack.

The United States has the ability to turn its offensive cyberweapons against ransomware operators. Cyber Command, the military’s still-new force of cyberwarriors, went after TrickBot last fall, another ransomware group, to keep it from selling its services to groups seeking to disrupt the 2020 presidential election.

Mr. Biden noted that Darkside is based in Russia, but he said American intelligence agencies do not believe that President Vladimir V. Putin of Russia or the Russian government were involved in the attack on the pipeline.

“I am confident that I read the report of the F.B.I. accurately. And they say, they were not, he was not. The government was not,” the president said.

For the Biden White House, the attack on the Colonial Pipeline has many elements of peril: Political peril as Americans along the East Coast line up to get gas; economic peril as the administration worries about the temporary effects on air travel and chemical production; and technological peril as experts try to figure out how a ransomware attack turned into a national security event.

Mr. Biden sought to address all three issues Thursday. He said his administration had eased regulations to allow companies to deliver gas more easily in the affected regions and eased environmental rules temporarily to provide flexibility for gas companies.

He also urged American in the affected regions to avoid panicked buying of gasoline.

“This is a temporary situation. Do not get more gas than you need in the next few days,” he said, adding that “We expect the situation to begin to improve by the weekend and into early next week, and gasoline supply is coming back online, and panic buying will only slow the process.”

The president also mentioned the administration’s executive order on cybersecurity that was published on Wednesday night, which sets security standards for any company that is looking to sell software to the federal government.

The move is part of a broad effort to strengthen the United States’ defenses by encouraging private companies to practice better cybersecurity or risk being locked out of federal contracts. But the bigger effect may arise from its effects on the industry. Over time, the hope is that a federal rating on cybersecurity would become akin to the way automobiles get a safety rating or restaurants in New York get a health safety grade.

“I cannot dictate that the private companies do certain things relative to cybersecurity,” Mr. Biden told reporters. But he said that “I think it’s becoming clear to everyone that we have to do more than being done now and the federal government can be significant value added.”

Mr. Biden said the attack on the pipeline should underscore the need for the United States to improve its critical infrastructure, and urged lawmakers to back his $2.3 trillion proposal to rebuild roads, bridges, pipelines and other projects.