The chairman of the Senate Intelligence Committee said hackers listened to phone calls and read texts by exploiting aging equipment and seams in the networks that connect systems.

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.

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.

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