WikiLeaks has published thousands of documents that it claims detail the US Central Intelligence Agency's covert hacking program and the development of devastating cyberweapons.
The anti-secrecy website claims the 8,761 documents dated from 2013 to 2016 are from an "isolated, high-security network" in the CIA's suburban Washington headquarters and detail how it can take control of mobile phones, computer operating systems and even smart televisions to spy on targets.
The documents detail a program developed along with British intelligence called "Weeping Angel" that allows spies to secretly take control of a Samsung smart TV and turn it into a listening device even when it appears to be off.
The CIA also operated branches to develop attacks on iPhones and Android phones that can send the user's data and secretly activate the camera and microphone.
By taking control of the phone, the agency is able to bypass encrypted apps such as WhatsApp.
The leaks also appear to show that the US consulate in Frankfurt was used as part of CIA hacking operations in Europe, Africa and the Middle East, with agents using diplomatic cover while in Germany.
The CIA said it would not comment on the report.
"We do not comment on the authenticity or content of purported intelligence documents," spokesman Jonathan Liu said.
White House spokesman Sean Spicer said the leak had "not been fully evaluated, and if it was, I would not comment from here on that."
WikiLeaks said the CIA had lost control of its hacking arsenal and that it had been circulated among former US government hackers and contractors, including one who had provided the material to WikiLeaks in hopes of starting a debate about cyberweapons.
WikiLeaks founder Julian Assange claimed the documents show the risk of proliferation of cyberweapons, and said the organisation had withheld some information "until a consensus emerges on the technical and political nature of the CIA's program and how such 'weapons' should analysed, disarmed and published."
The publication is larger than that provided by Edward Snowden's leak of National Security Agency (NSA) documents, WikiLeaks said.
The organisation criticised the CIA for in effect creating a parallel NSA, "with even less accountability."