Hit by a cyberattack, the operator of a major US fuel pipeline said it hopes to have services mostly restored by the end of the week as the FBI and administration officials identified the culprits as a gang of criminal hackers.

US officials sought to soothe concerns about price spikes or damage to the economy by stressing that the fuel supply had so far not experienced widespread disruptions, and the company said on Monday that it was working toward “substantially restoring operational service” by the weekend.

The White House said in a statement late Monday that it was monitoring supply shortages in parts of the Southeast and that President Joe Biden had directed federal agencies to bring their resources to bear.

Colonial Pipeline, which delivers about 45% of the fuel consumed on the East Coast, halted operations last week after revealing a ransomware attack that it said had affected some of its systems.

Nonetheless, the attack underscored the vulnerabilities of the nation's energy sector and other critical industries whose infrastructure is largely privately owned. Ransomware attacks are typically carried out by criminal hackers who scramble data, paralyzing victim networks, and demand large payments to decrypt it.

The Colonial attack was a potent reminder of the real-world implications of the burgeoning threat. Even as the Biden administration works to confront organized hacking campaigns sponsored by foreign governments, it must still contend with difficult-to-prevent attacks from cybercriminals.

"We need to invest to safeguard our critical infrastructure,” Biden said on Monday. Energy Secretary Jennifer Granholm said the attack “tells you how utterly vulnerable we are” to cyberattacks on U.S. Infrastructure.

The attack came as the administration, still grappling with its response to massive breaches by Russia of federal agencies and private corporations, works on an executive order aimed at bolstering cybersecurity defenses.