CLEMMONS, N.C. • Motorists found gas pumps shrouded in plastic bags at tapped-out service stations across more than a dozen U.S. states Thursday while the operator of the nation’s largest gasoline pipeline reported making “substantial progress” in resolving the computer hack-induced shutdown responsible for the empty tanks.

About 70% of North Carolina’s gas stations were still without fuel amid panic-buying and about half the stations in Virginia, South Carolina and Georgia were tapped out, GasBuddy. com reported. Washington, D.C., was among the hardest-hit locations, with 73% of stations out, the site’s tracking service showed.

President Joe Biden said Thursday that U.S. officials do not believe the Russian government was involved in the hack of the Colonial Pipeline, which stretches from Texas to New Jersey. But he added, “We do have strong reason to believe that the criminals who did the attack are living in Russia. That’s where it came from.”

A cyberattack by hackers who lock up computer systems and demand a ransom to release them hit the pipeline on Friday. The hackers did not take control of the pipeline’s operations, but Colonial shut it down to contain the damage.

The U.S. was in direct communication with Moscow about the need to take action against ransom networks, Biden said. The FBI has said the ransomware belonged to a criminal syndicate known as DarkSide.

After restarting operations Wednesday, Georgia-based Colonial Pipeline said in a Thursday update that gasoline deliveries were underway in all of its markets. It will take “several days” for things to return to normal, and some areas may experience “intermittent service interruptions during this start-up period,” the company said.

The Northeast has seen fewer shortages since those states get more of their gas supplies from ocean tankers and other sources. The Colonial Pipeline delivers about 45% of the gasoline consumed on the East Coast, but there were no gasoline shortages, according to government officials and energy analysts, just delays in delivering the fuel from Gulf Coast refineries.

“We are not out of the woods yet, but the trees are thinning out,” Richard Joswick, global head of oil analytics at S&P Global Platts, said.

Gas stations should be back to normal next week, though, if the pipeline restart goes as planned and consumers are convinced that they no longer need to panic-buy fuel, Joswick said. He estimated that full recovery for the East and Gulf coasts would take at least a couple of weeks.

In Virginia, however, the pipeline shutdown still produced palpable effects Thursday. Stephen Brich, the Virginia Department of Transportation highways commissioner, said the agency is limiting nonessential travel and asking its employees to continue working remotely as a conservation strategy. The decision impacts about 4,000 workers.

Workers are still responding to emergency issues such as potholes, malfunctioning traffic signals, guard rail problems, drainage issues and bridge issues. There are sufficient supplies of unleaded and diesel fuel to maintain services for several more weeks, Brich said.

The run on gas also prompted an urgent warning in the state that people should never siphon gasoline off by mouth with hoses, an advisory that followed calls in recent days about people who were poisoned. One man sucked gasoline into his lungs, causing significant distress, Dr. Chris Holstege, the medical director of the Blue Ridge Poison center at UVA Health, said.

The governors of both Virginia and North Carolina declared states of emergency to help ensure access to gasoline. Other governors urged people not to hoard supplies.