A former CIA engineer who was charged with possession of child pornography has also been charged with leaking thousands of classified documents to WikiLeaks.

US federal prosecutors said in a statement that Joshua Schulte allegedly leaked classified national defense information.

Schulte, a New York City resident, was charged in a 13-count superseding indictment connected to alleged theft of classified information from the CIA, the US Attorney's Office for the Southern District of New York said in a joint statement with US Justice Department and FBI officials.

Manhattan attorney, Geoffrey Berman, said that Schulte allegedly 'used his access at the agency to transmit classified material to an outside organization'.

'Unlawful disclosure of classified intelligence can pose a grave threat to our national security, potentially endangering the safety of Americans,' Berman added.

Joshua Schulte, a former CIA engineer who was charged with possession of child pornography, has also been charged with leaking thousands of classified documents to WikiLeaks

US federal prosecutors said in a statement that Schulte allegedly leaked national defense information and charged him in a 13-count superseding indictment connected to alleged theft of classified information from the CIA

The indictment also charged Schulte with the receipt, possession and transportation of child pornography.

According to the indictment, in March and June of 2016 Schulte altered a computer system operated by the US Intelligence Agency to grant himself access to the system, enabling him to delete records of his activities and deny others access to the system.

In January, a prosecutor said Schulte was the target of an ongoing investigation into the theft of tools that were used by the CIA to spy overseas.

In March 2017, the FBI searched Schulte's Manhattan apartment for information linking him to the breach.

The FBI said they removed NSA and CIA paperwork from Schulte's home, as well as a personal computer, tablet, phone and other electronics.

Around the same time, WikiLeaks began releasing some of the CIA's hacking tools, including software exploits designed to take over iPhones and turn smart TVs into surveillance devices.

The US government has all but publicly acknowledged the embarrassing leak from the CIA's Center for Cyber Intelligence.

President Donald Trump told a television host at the time: 'I just want people to know the CIA was hacked, and a lot of things taken.'

The breach, known as Vault 7, was the largest loss of classified documents in the agency's history, according to The New York Times.

The indictment sought the forfeiture of any property Schulte obtained directly or indirectly from any foreign government, party or military force as a result of the crimes.

Schulte was arrested in August, but prosecutors had been unable to bring charges against him until now.

According to the Times, FBI agents said they found images of children being molested by adults on a server Schulte created as a business in 2009 while he was a student at the University of Texas.

Court documents suggest that Schulte was aware of the images and had warned one user not to 'put anything too illegal on there'.

Schulte, 29, worked at the CIA (file image) as a software engineer who helped design malware used to break into the computers of terrorism suspects and other targets. He left in 2016

In September, a month after his arrest, Schulte was released on the condition he not leave New York City, where he had been living with a relative. He was thrown back in jail in December when he violated that order.

Schulte has been housed at the Metropolitan Correctional Center ever since.

He has denied the child pornography charges claiming that around 50 to 100 people had access to the server he created, according to the Washington Post.

Schulte also said that because of 'unfortunate circumstances the FBI ultimately made the snap judgement that [he] was guilty of the leaks and targeted [him]'.

According to the former CIA engineer, he had been planning a trip to Mexico with his brother around the time his apartment was searched, which may have given the appearance that he was trying to flee the country.

The FBI stopped Schulte from traveling to Mexico and took his passport.

Schulte worked at the agency as a software engineer who helped design malware used to break into the computers of terrorism suspects and other targets. He left the CIA in 2016 to work in the private sector.

His lawyer, Sabrina Shroff, said in May that her client was 'deeply saddened' that he might face espionage-related charges.

On Monday, she said: 'When all the evidence is clear, he's hardly the villain that the government tries to make him out to be.'

Since he's been jailed, Schulte has created a Facebook page where he posts articles criticizing the criminal justice system.

He also launched a GoFundMe to raise $50million for his legal expenses. The GoFundMe does not have any donations.

Schulte faces various new charges, including illegal gathering of national defense information, illegal transmission of lawfully possessed national defense information, unauthorized access to a computer to obtain classified information, theft of government property, causing transmission of a harmful computer program, information, code or command.

Included among the charges was an allegation that he engaged in criminal copyright infringement from September 2015 to last August by making publicly available on a computer network thousands of copyrighted movies, television shows and audio recordings.

If convicted, he could face decades in prison.