Top US fuel pipeline operator Colonial Pipeline shut its entire network, the source of nearly half of the US East Coast's fuel supply, after a cyber attack on Friday that involved ransomware.

The incident is one of the most disruptive digital ransom operations ever reported and has drawn attention to how vulnerable US energy infrastructure is to hackers. A prolonged shutdown of the line would cause prices to spike at gasoline pumps ahead of peak summer driving season, a potential blow to US consumers and the economy...