The CIA and FBI have reportedly launched a manhunt for the person responsible for leaking thousands of top secret documents describing the CIA's cyberspying capabilities and tools. In March, WikiLeaks published a trove of damaging files in an ongoing series of "Vault 7" leaks exposing the CIA's wide-ranging tools and hacking capabilities used to snoop on various smartphones, smart televisions, computer systems, software and other devices.

Citing sources familiar with the investigation, CBS reports the CIA and FBI are looking for an insider believed to be a CIA employee or contractor who had physical access to the material. However, they did not publicly specify when or how the material was stolen from the agency.

Describing the series of leaks as the "largest ever publication of confidential documents on the agency", WikiLeaks previously said the documents and files came from "an isolated, high-security network situated inside the CIA's Center for Cyber Intelligence in Langley, Virginia".

The notorious whistle-blowing site previously said the CIA recently "lost control of the majority of its hacking arsenal" ranging from malware and trojans to zero day exploits and malware remote control systems. The massive archive was apparently circulated among former US government hackers and contractors "in an unauthorised manner," WikiLeaks said.

WikiLeaks said it obtained the material from former contractors who worked for US intelligence.

Hundreds of employees and contractors are said to have access to the documents held in a highly-secure part of the CIA, the sources said. Investigators are beginning to work through those names.

While the CIA has yet to comment on the authenticity of WikiLeaks' disclosures, multiple high-profile tech companies scrambled to detect and fix security flaws to protect their products following the leaks.

The CIA and FBI have reportedly launched a manhunt for the person responsible for leaking damaging CIA material to WikiLeaks Reuters/Larry Downing

Last week, CIA director Mike Pompeo slammed WikiLeaks in his first public comments as spy agency chief calling the group a "hostile intelligence service". He also accused founder Julian Assange and Edward Snowden, a former contractor who leaked NSA documents to journalists in 2013, of seeking to use sensitive information to "make a name for themselves".

"As long as they make a splash, they care nothing about the lives they put at risk or the damage they cause to national security," Pompeo said. "It is time to call out WikiLeaks for what it really is — a non-state hostile intelligence service often abetted by state actors like Russia.

"Assange claims to harbor an overwhelming admiration for both America and the idea of America. But I assure you that this man knows nothing of America and our ideals... We have to recognize that we can no longer allow Assange and his colleagues the latitude to use free speech values against us. To give them the space to crush us with misappropriated secrets is a perversion of what our great Constitution stands for. It ends now."

Assange fired back at Pompeo's comments saying the CIA is "trying to get ahead of the publicity curve and create a preemptive defense".

"For the head of the CIA to pronounce what the boundaries are, of reporting or not reporting — is a very disturbing precedent," Assange said during an Intercepted podcast, speaking from the Ecuadorian embassy in London where he has been residing since 2012.

"The head of the CIA determining who is a publisher, who's not a publisher, who's a journalist, who's not a journalist, is totally out of line.

"So how does he propose to conduct this ending? He didn't say. But the CIA is only in the business of collecting information, kidnapping people, and assassinating people. So, it's quite a menacing statement that he does need to clarify."