A Georgia-based company that operates the most extensive fuel pipeline system in the U.S. has shut down its activities due to a cyberattack.

Colonial Pipeline announced Saturday that it would be ceasing its pipeline operations and that the closure would affect some of its IT customers.

“Upon learning of the issue, a leading, third-party cybersecurity firm was engaged, and they have already launched an investigation into the nature and scope of this incident, which is ongoing. We have contacted law enforcement and other federal agencies,” the statement read.

The massive 5,500-mile pipeline operates between Houston, Texas, and Linden, New Jersey.

Colonial Pipeline is the biggest refined products pipeline in the nation and transports about 45 percent of the East Coast’s fuel, according to the company website.

The company said it is moving towards resolving this issue.

“At this time, our primary focus is the safe and efficient restoration of our service and our efforts to return to normal operation. This process is already underway, and we are working diligently to address this matter and to minimize disruption to our customers and those who rely on Colonial Pipeline,” the statement continued.

It is unclear who was behind the cyberattack.

The company said it contacted law enforcement and related federal agencies to investigate.