John Bolton, who served as Donald Trump's national security adviser and later became known for his harsh criticism of the president, has been indicted on federal criminal charges.

The Justice Department has filed charges in Maryland, saying it has sufficient information. They have released a statement saying they are not guilty.

In August, FBI agents searched Bolton's home and office as part of an investigation into the leak of classified information.

Bolton, 76, is the third person in recent weeks to be indicted as an opponent of the US president. If convicted, he could face decades in prison.

According to a 26-page indictment filed in a court in Greenbelt, Maryland, Bolton is charged with eight counts of transmitting national defense information and 10 counts of illegally retaining national defense information.

Prosecutors have accused him of illegally transmitting classified US defense information using his private email and other messaging apps.

"These documents contain information about future attacks, foreign adversaries and foreign policy communications," it’s said.