The United States Justice Department on Thursday indicted former President Donald Trump on charges of mishandling classified documents.

While the federal charges are not yet public, Trump confirmed the development on his social media, Truth Social. Trump faces seven charges, including unauthorised retention of classified materials under the Espionage Act, according to The New York Times.

In August, the Federal Bureau of Investigation agents seized documents marked “top secret” during a search of Trump’s estate in Florida.

A property receipt released showed that some of the seized materials were labelled as “top secret’ and “sensitive compartmented information” – one of the highest levels of classification. Information categorised in such a manner is meant to be accessed only in a secure government facility. Trump claims that the documents were de-classified.

This is the first time a former US president is facing criminal charges by the federal government. In March, Trump was indicted by a Manhattan jury in a criminal case related to making payments during his 2016 presidential campaign bid to silence an adult film actor.

If Trump is found guilty in the latest case, he can end up in prison, reported the Associated Press. This can also upend his campaign for the presidential election in 2024.

On Thursday, Trump said that his attorneys were informed about the development by “the corrupt Joe Biden administration”.

The former president added that he has been asked to appear before a federal court in Miami at 3 pm on Tuesday.

“I never thought it possible that such a thing could happen to a former president of the United States,” Trump wrote. “This is indeed a dark day for the United States of America. We are a country in serious and rapid decline, but together we will make America great again!”