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.

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.

National security officials say hackers linked to the Chinese government breached telecommunications companies, including Verizon and AT&T, stealing data from over a million Americans. The hack targeted government and political figures, including President-elect Donald Trump and his running mate, with some having voice recordings and texts stolen.

Chinese hackers compromised eight American telecommunications companies as part of a wide-ranging espionage effort to gather intelligence about prominent US citizens, Biden administration officials said Wednesday.

There have been reports since early October that Chinese government hackers penetrated the networks of telecoms and may have gained access to systems used for court-authorized wiretaps of communications networks. Impacted telcos reportedly include Verizon, AT&T, T-Mobile, and Lumen (also known as CenturyLink).

The Biden administration is working closely with at least eight U.S. telecommunications providers that have been breached by Chinese hackers as part of a broad global spying campaign.

A top White House official says at least eight U.S. telecom firms and dozens of nations have been impacted by a Chinese hacking campaign

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,

At least eight U.S. telecommunications firms were compromised in the attack, a senior White House official said.