A ransomware attack led one of the nation’s biggest fuel pipeline operators to shut down its entire network on Friday, according to the company and two U.S. officials familiar with the matter.

While it is not expected to have an immediate impact on fuel supply or prices, the attack on Colonial Pipeline, which carries almost half of the gasoline, diesel and other fuels used on the East Coast, underscores the potential vulnerability of industrial sectors to the expanding threat of ransomware strikes.

It appears to have been carried out by an Eastern European-based criminal gang — DarkSide, according to a U.S. official and another person familiar with the matter.

Read more: The Washington Post