The FBI and CISA previously said they were investigating breaches by a China-backed hacking group inside several telecommunications providers, but had not said whether any data was stolen or whether the hackers accessed the systems used to fulfill legal wiretap requests.

The disclosure is the latest sign that the Chinese burrowed deep inside U.S. communications networks in a far-reaching espionage campaign.

An FBI investigation into reported hacks at AT&T and Verizon reveals 'a broad and significant cyber espionage campaign,' the agency says.

CISA and the FBI have confirmed that Chinese hackers compromised the networks of telecommunications companies to spy on specific targets.

China-affiliated actors "have compromised networks at multiple telecommunications companies" to enable the theft of U.S. customer call records and access to the private communications of some individuals involved in government or politics,

The U.S. government has confirmed that hackers with links to China breached multiple U.S. telecommunication service providers to access the wiretap systems used by law enforcement to surveil Americans.

A federal investigation into Chinese government efforts to hack into U.S. telecommunications networks has revealed a “broad and significant” cyberespionage campaign aimed at stealing information from Americans who work in government and politics,

WASHINGTON (Reuters) -China-linked hackers have intercepted surveillance data intended for American law enforcement agencies after breaking in to an unspecified number of telecom companies, U.S. authorities said on Wednesday.