A Chinese hacking campaign that has spied on the texts and calls of U.S. citizens by hacking telecommunications companies is significantly larger than previously known to the public, a top White House official said Wednesday.

US officials believe Chinese hackers breached at least eight US telecommunications providers in their quest to spy on top US political figures as part of a hacking campaign that has affected dozens of countries worldwide,

A large number of Americans' metadata has been stolen in the sweeping cyberespionage campaign carried out by a Chinese hacking group dubbed "Salt Typhoon," a senior U.S. official told journalists on Wednesday.