The FBI and the Cybersecurity and Infrastructure Security Agency (CISA) said that People's Republic of China (PRC) hackers breached commercial telecommunication service providers in the U.S.

The breached entities have been warned, and the agencies are proactively alerting other potential targets of elevated cyber activity.

"The U.S. government's continued investigation into the People's Republic of China (PRC) targeting of commercial telecommunications infrastructure has revealed a broad and significant cyber espionage campaign," the agencies said Wednesday in a joint release.

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The agencies said that PRC-affiliated actors have compromised networks at multiple telecommunications companies to enable the theft of customer call record data, as well as private communications of a "limited number of individuals who are primarily involved in government or political activity."

The joint statement said that the PRC actors also copied "certain information that was subject to U.S. law enforcement requests pursuant to court orders."

"We expect our understanding of these compromises to grow as the investigation continues," the agencies noted.

The agencies said that they are working to "strengthen cyber defenses," and encouraged organizations that believe they were impacted to contact their local FBI field office or CISA.

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"The FBI and the CISA continue to render technical assistance, rapidly share information to assist other potential victims, and work to strengthen cyber defenses across the commercial communications sector," the agencies said. "We encourage any organization that believes it might be a victim to engage its local FBI Field Office or CISA."

The reports of continued Chinese interference in the U.S. come after hackers targeted President-elect Trump and Vice President Kamala Harris' campaigns during the thick of the race for the White House.

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"After the FBI identified specific malicious activity targeting the sector, the FBI and the Cybersecurity and Infrastructure Security Agency (CISA) immediately notified affected companies, rendered technical assistance, and rapidly shared information to assist other potential victims," the FBI and CISA previously told Fox News Digital in a joint statement.

Fox News Digital has reached out to the FBI for comment.