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.

Chinese hackers are actively listening in on calls and intercepting communications in real time, says a US senator.

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.

Republican South Dakota Senator Mike Rounds issued a stark warning on Friday, revealing that Chinese state-sponsored hackers, known as "Salt Typhoon," have infiltrated all major U.S. telecommunications networks.