“Resumption of flows is the start, but the race to logistically replenish retail gas stations is the next step,” said Michael Tran, an analyst at RBC Capital Markets. “The restarting of the Colonial pipeline is the beginning of the end of the crisis, not the end.”

The news came as gasoline stations were running dry from Florida to Virginia after Colonial was forced to take systems offline on May 7. In parts of the U.S. South, three in every four gas stations had no fuel as of Wednesday, while in Washington, D.C., cars were lining up for blocks as they waited to fill up. U.S. pump prices have topped $3 a gallon for the first time in six years. Colonial each day normally ships about 2.5 million barrels (105 million gallons), an amount that exceeds the entire oil consumption of Germany.

The disruption underscores just how vulnerable America’s fuel supply system has become in the wake of increased attacks on energy infrastructure by hackers over the past few years. Colonial is only the latest example of critical infrastructure being targeted by ransomware. Hackers are increasingly attempting to infiltrate essential services such as electric grids and hospitals.

The attack on Colonial also came just as the nation’s energy industry is preparing for summer travel and as fuel demand rebounds from pandemic-related lockdowns. It was reminiscent of a 2018 cyberattack that brought down a third-party communications system used by several natural gas pipelines operators across the U.S.

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In North Carolina, some fuel supply should appear right away as Colonial restarts, and a significant change should register by this weekend, said Gary Harris, executive director of the North Carolina Petroleum & Convenience Marketers, a trade association.

“People will have to be running trucks a lot to just catch up because so much is out at this time,” he said.

Major branded stations will get fuel first as they are under contract with suppliers, said Harris. Fuel may still be scarce for independent stations that are not under contract.

Royal Dutch Shell Plc said it was pursuing alternative supply points, where possible, and working in close coordination with wholesalers to address supply and logistical challenges.

In Virginia, consumers should be able to see a difference by Monday, said Michael O’Connor, president of the Virginia Petroleum & Convenience Marketers Association.

Also See: Atlanta’s Fuel Crisis Sparks Hunt for Increasingly Rare Supply

The Federal Bureau of Investigation attributed the attack on Colonial to ransomware created by a group called DarkSide. Some evidence emerged linking DarkSide to Russia or elsewhere in Eastern Europe. President Joe Biden said Russia has “some responsibility” to address the attack but stopped short of blaming the Kremlin, saying “there’s evidence” the hackers or the software they used are “in Russia.”

Shortly before the Colonial announcement, President Joe Biden said he was expecting good news on the situation and touted the steps he had taken to relieve supply disruptions.

“I’ve lifted some of the restrictions on the transportation of fuel as well as access to the United States military providing fuel, and with vehicles to get it there, places where it’s badly needed,” Biden told reporters at the White House.

The White House announced several measures to blunt the growing crisis, including waiving some gasoline requirements and empowering 10 states to allow heavier-than-normal truck loads of fuels.

Also See: Biden Signs Order to Bolster Cyber-Security After Pipeline Hack

This isn’t the first time Colonial has been forced to shut down. In 2016, an explosion kept the system offline for days, raising gasoline prices and forcing the New York Harbor market to become more dependent on imports of fuel from overseas.