US motorists have been urged to not hoard fuel as supplies tighten due to a major pipeline remaining shut after a cyber-attack.
Some drivers in the south east were seen stocking up as petrol stations began running dry and prices rose.
The average price for petrol was the highest on Tuesday since November 2014, at $2.98 (£2.11) per gallon, the American Automobile Association said.
North Carolina, Virginia and Florida have declared a state of emergency.
But US Energy Secretary Jennifer Granholm said there was no need for motorists to hoard petrol.
Ms Granholm said there was not a shortage but a supply “crunch” in North Carolina, South Carolina, Tennessee, Georgia and southern Virginia, regions that typically rely on Colonial for fuel.
A ransomware cyber-attack on Friday forced Colonial Pipeline to shut down the main part of its network.
The operator has forecast that it will not substantially restore operations of the 5,500-mile (8,900km) pipeline network that supplies nearly half of the East Coast’s fuel until the end of the week.
The FBI has accused a criminal gang called DarkSide of the ransomware attack.
The gang is believed to be based in Russia or Eastern Europe and avoids targeting computers that use languages from former Soviet republics, cyber experts said.
Ransomware is a type of malware designed to lock computers by encrypting data and demanding payment to regain access.
Russia’s embassy in the US rejected speculation that the country’s government was behind the attack.
President Joe Biden a day earlier said there was no evidence so far that Russia was responsible.
If the general public or politicians ever needed proof of how devastating cyber-attacks can be, this hack will more than suffice: chaos at the pumps, states of emergency declared and the White House calling for calm.
And this is just the stuff we’re being told about.
In Colonial Pipeline’s latest press update, we’re given hints about the mayhem inside the company.
With high-tech sensors and safety systems taken offline, the firm says it’s hired dozens of staff to walk or drive the 5,000-mile length of the pipeline every day.
It’s also deployed helicopters to check on the pipes and a growing fleet of delivery trucks.
Another clue to the chaos is that the company’s website has been periodically taken offline.
Colonial says this is a separate problem, but tellingly it has now blocked all traffic from outside of the US.
Even the hackers themselves seem surprised by the damage they’ve caused.
According to new research from cyber-security company FireEye, the hackers known as Darkside launched their global crime spree in August last year, raking in millions from organisations in more than 15 countries.
But this hack seems like it may have crossed some sort of line even for these hardened criminals. The true test of their morals, though, will depend on whether or not they will continue the extort the company or help it recover.