Executives from leading U.S. telecommunications companies met with U.S. national security officials at the White House amid growing concerns about cyber espionage from China, CNN reported. According to the channel, about 150 high-ranking officials and politicians in the United States could become victims of surveillance.

According to the White House, such meetings are needed to advise Washington on how the government can strengthen its defense against cyber hacking, DW reports. Participants also share intelligence as part of the dialog.

The incident was “by far the worst telecommunications hack in the history of our country,” Sen. Mark Warner told CNN. According to the politician, the extent of the hack, its consequences and its impact on national security are still being clarified. However, the FBI has notified more than 150 victims of the cyberattack, most of them in the Washington, D.C. area, Warner told CNN. Since they all made calls and sent text messages, the hackers from China likely accessed the data of many more people.

Earlier, it was revealed that China attempted to wiretap President-elect Donald Trump, Vice President-elect J.D. Vance, as well as Trump's son-in-law Jared Kushner and his son Eric. China denies accusations of cyberattacks and espionage.