Trump's former national security adviser indicted: What are the charges against John Bolton?

The charges against Bolton come shortly after Justice Department indicted former FBI director James Comey and New York Attorney General Letitia James.

Trump's former national security adviser John Bolton was indicted by a federal grand jury in Maryland on Thursday, according to court records cited by Reuters news agency.

Bolton, formerly a close adviser to the US President, has now turned into a critic.(AFP)

Bolton, formerly a close adviser to the US President, has now turned into a critic, and becomes the third high-profile Trump adversary to be indicted in less than a month. The charges against Bolton come shortly after Justice Department indicted former FBI director James Comey and New York Attorney General Letitia James.

He is expected to surrender himself to authorities at the federal court in Greenbelt as soon as Friday, CNN reported.

Bolton has previously served as the US ambassador to United Nations as well as the national security adviser to the White House.

What are the charges against John Bolton?

Bolton has been under investigation for alleged unlawful handling of classified information. He allegedly shared highly classified information with his wife and daughter over email, CNN reported citing sources.

He was indicted on charges of retaining and transmitting national defense information. Court records made public last month had revealed that a fresh probe had been launched against Bolton for potential mishandling classified information.

In a statement, Bolton's Abbe lawyer said Lowell said that charges stemmed from unclassified personal diaries Bolton shared with his immediate family. Lowell said Bolton did not unlawfully share or store any information.

According to sources cited by the CNN, part of the investigation against Bolton is centred around notes he was making to himself in an AOL email account when he was working for Trump. These included summaries of his activities made in the form of diary entries.

The indictment comes after FBI agents executed a search warrant on Bolton's home in Maryland and his Washington office during the summer. The agents had reportedly found multiple documents labeled “secret”, “confidential” and “classified”, including some about weapons of mass destruction, according to court records.