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

Verizon Communications, AT&T and Lumen Technologies are among the telecoms companies whose networks were breached by the recently discovered intrusion, the newspaper said, citing people familiar with the matter.

The hackers might have held access for months to network infrastructure used by the companies to cooperate with court-authorized U.S. requests for communications data, the newspaper said. It said the hackers had also accessed other tranches of internet traffic.

China’s foreign ministry did not immediately respond to a Reuters request for comment. Beijing has in the past denied claims by the U.S. government and others that it has used hackers to break into foreign computer systems.

Verizon Communications, AT&T and Lumen Technologies did not immediately respond to a request for comment.

The Wall Street Journal said the attack was carried out by a Chinese hacking group with the aim of collecting intelligence. U.S. investigators have dubbed it “Salt Typhoon”.

Earlier this year, U.S. law enforcement disrupted a major Chinese hacking group nicknamed “Flax Typhoon,” months after confronting Beijing about sweeping cyber espionage under a campaign named “Volt Typhoon.”

(Reporting by Shivani Tanna in Bengaluru and Beijing newsroom; Editing by Edmund Klamann)