The breach, traced to Chinese state-sponsored hackers, may have lasted for months, according to The Wall Street Journal.

The Salt Typhoon breach is just the latest example of Chinese hacking groups targeting US networks. In recent months, other Chinese-linked campaigns, such as Volt Typhoon and Flax Typhoon, have also been identified as threats.

The intrusion affected major telecom company networks that cooperate with court-authorized U.S. requests for communications data, according to a recent report.

The US is in the early stages of an investigation into potential Chinese hacking of American telecommunications companies, according to a top intelligence official.

A Chinese hacking group, reportedly connected to the country’s government, has breached several U.S. telcos in recent months, the Wall Street Journal reported on Friday citing sources familiar with the matter. The sources suggest that telecoms and broadband providers, including AT&T, Verizon, and Lumen, were among the targets of these attacks.

The director of the National Security Agency said Sunday a Chinese hack of three major telecommunications firms is under investigation, but it remains “premature” to discuss the case.

(Reuters) -Chinese hackers accessed the networks of U.S. broadband providers and obtained information from systems the federal government uses for court-authorized wiretapping, the Wall Street Journal reported on Saturday.

A highly skilled group of Chinese government-linked hackers has in the last several months infiltrated multiple US telecommunications firms in a likely search for sensitive information bearing on national security,