Donald Trump took secret documents dealing with US nuclear and weapons programs from the White House after leaving office, potentially putting national security at risk, according to the indictment of the former president unsealed on Friday.

The 76-year-old Trump, the frontrunner for the 2024 Republican presidential nomination, took "hundreds" of classified government documents to his Mar-a-Lago residence and club in Florida, the 49-page charge sheet said.

Trump kept the files, which included documents from the Pentagon, CIA and National Security Agency, unsecured at Mar-a-Lago, which regularly hosted large social events involving tens of thousands of guests over time, the indictment said.

On at least two occasions, Trump showed classified documents on US military operations and plans to people not cleared to see them at his Bedminster, New Jersey, golf club, it said.

Trump faces 37 separate counts in the indictment including 31 counts of "willful retention of national defense information," which carries up to 10 years in prison on each count.

Other charges include conspiracy to obstruct justice, withholding a document and false statements. 

"The classified documents Trump stored in the boxes included information regarding defense and weapons capabilities of both the United States and foreign countries," the indictment said.

Other records dealt with US nuclear programs and the potential vulnerabilities of the United States and its allies to military attack along with plans for retaliation, it said.

"The unauthorized disclosure of these classified documents could put at risk the national security of the Untied States, foreign relations, the safety of the United States military, and human sources," according to the indictment.

- Court appearance -

Trump is to appear in court in Miami on Tuesday for an initial hearing in the case, the first ever in which a former US president faces federal criminal charges.

Trump announced on his Truth Social platform Thursday that he had been indicted by the "corrupt Biden Administration" in what he called the "Boxes Hoax."

In a defiant video, Trump repeatedly declared his innocence and framed the indictment as election interference by a Justice Department "weaponized" by the administration of Democratic President Joe Biden.

"They come after me because now we're leading in the polls again by a lot against Biden," Trump said in the clip.

Trump was already the first former or sitting president to be charged with a crime -- in his case over election-eve hush money payments to a porn star who said she had an affair with him.

That indictment was handed down by Manhattan's district attorney in March.

The classified documents investigation was carried out by a special counsel, Jack Smith, who was named by Attorney General Merrick Garland.

Smith is also looking into whether Trump should face charges over the January 2021 assault on the US Capitol by his supporters.

And Georgia prosecutors are investigating whether Trump illegally attempted to overturn the 2020 presidential election outcome in the southern state. 

cl/mlm