Coast Guard, FBI investigating after 2 oil tankers bound for US hit with cyberattacks

U.S. authorities said there were no reports of "operational disruptions."

The Coast Guard and FBI are investigating after two oil tankers bound for the U.S. were hit with suspected cyberattacks last month, prompting American authorities to launch investigations into both incidents, sources told ABC News.

On Aug. 21, one of the tankers, described as a "foreign-flagged commercial vessel" was boarded by a "highly specialized team" of U.S. Coast Guard law enforcement officers, cyber protection members and an FBI cyber team in the Gulf of Mexico, according to a joint statement from both agencies.

"The measures were designed to ensure integrity of the vessel’s operational and information technology systems following indications that the vessel’s network were compromised by foreign cyber actors," the statement said.

That vessel was in the Strait of Gibraltar when it was hacked, according to sources, and lost communication for over 30 hours. 

The joint statement said the ship's crew members cooperated with authorities and were "critical partners in helping to ensure the threats were mitigated" and concluded: "Currently, there are no reports of operational disruptions, vessel instability, physical danger to crews, or environmental impacts."

Sources told ABC News that another tanker that was hit by a cyberattack was boarded by U.S. officials on Aug. 24. to conduct a similar assessment. 

Authorities are investigating the possibility that Iran or another actor -- seeking to exploit the ongoing conflict between Iran and U.S. -- was involved in attacks, according to the sources.

"Currently, there are no reports of operational disruptions, vessel instability, physical danger to crews, or environmental impacts," the joint statement released by the Coast Guard and FBI said.