All the major U.S. carriers, including AT&T, Verizon, and T-Mobile, were impacted, according to the Post. Incredibly, Warner says the hackers are still inside the U.S. system and there’s no obvious way to get them out that doesn’t involve physically replacing old equipment, according to Warner.

A breach of telecoms companies that the United States said was linked to China was the "worst telecom hack in our nation's history - by far", the chairman of the Senate Intelligence Committee told the Washington Post on Thursday.

Telecoms hack on US government officials is 'worst in nations history' and 'the barn door is still wide open' says senator

The telecommunications hack earlier this month linked to Chinese hackers was the worst in U.S. history, according to the chairman of the Senate Intelligence Committee. The FBI and the Cybersecurity and Infrastructure Security Agency (CISA) announced in mid-November that the intelligence community identified that Chinese-linked actors "have compromised networks at multiple telecommunications companies to enable the theft of customer call records data,

The Chinese government espionage campaign that has deeply penetrated more than a dozen U.S. telecommunications companies is the “worst telecom hack in our nation’s history — by far,” a senior U.S. senator told The Washington Post in an interview this week.