Former US President Donald Trump has been charged over his handling of classified documents after he left the White House.
Mr Trump, 76, faces seven charges including mishandling classified documents, and obstructing efforts to investigate, his lawyer said.
Both are federal crimes which can carry a prison sentence on conviction.
Mr Trump is campaigning to make a return to the White House in 2024.
Legal experts say the indictment - the second time he has been charged with a crime - does not prevent him running for the presidency again.
In a post on Truth Social on Thursday, Mr Trump said he had been summoned to appear at a federal court in Miami, Florida, on Tuesday afternoon. He will be arrested at court and will hear the charges against him.
"I never thought it possible that such a thing could happen to a former president of the United States," Mr Trump wrote.
He added: "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!"
The charges have not yet been made public, but the details were laid out by his lawyer Jim Trusty. He told CNN they include conspiracy, false statements, obstruction of justice, and illegally retaining classified documents under the Espionage Act.
Mr Trump was at his golf club in Bedminster, New Jersey on Thursday when news of the indictment broke.
On Friday, the US Secret Service will meet Mr Trump's staff and security officers to plan his journey to the Miami courthouse next week.
The investigation into Trump's handling of classified documents has been overseen by special prosecutor Jack Smith, who has been considering evidence since he was appointed by Attorney General Merrick Garland in November.
Last year, Mr Trump's Florida resort Mar-a-Lago was searched by the FBI and 11,000 documents were seized. They included around 100 marked as classified, and some labelled top secret.
There were reports last week that prosecutors had obtained an audio recording of Mr Trump in which he acknowledged keeping a classified document after leaving the White House in January 2021.
It is against US law for federal officials - including a president - to remove or keep classified documents at an unauthorised location.
Legal experts say Mr Trump will still be able to enter the White House race.
"He can be indicted any number of times and it won't stop his ability to stand for office," says David Super, a professor at Georgetown University Law Centre.
Opinion polls show Mr Trump is currently the frontrunner for the Republican presidential nomination. He could continue running even if convicted in the documents case.
As Mr Trump issued a fundraising email with the subject line "BREAKING: INDICTED" on Thursday, several leading Republicans voiced their support for him.
Speaker of the House of Representatives, Kevin McCarthy, said it was "unconscionable for a president to indict the leading candidate opposing him".
"House Republicans will hold this brazen weaponisation of power accountable," he wrote on Twitter.
Mr Trump's rival for the 2024 nomination, Florida Governor Ron DeSantis said: "We have for years witnessed an uneven application of the law depending upon political affiliation.
"The DeSantis administration will bring accountability to the DOJ, excise political bias and end weaponisation once and for all."
Vivek Ramaswamy, who is also running, said he would "commit to pardon Trump promptly on January 20, 2025, and to restore the rule of law in our country".
But another candidate, Asa Hutchinson, said Mr Trump's alleged actions "should not define our nation or the Republican Party".
A separate probe into Mr Trump's role in the storming of the US Capitol is also being overseen by Jack Smith, a former war crimes attorney who is known as a dogged investigator.
Mr Trump became the first former president to be charged with a crime in April, after he pleaded not guilty to 34 counts of falsifying business records over a hush-money payment to a porn star.
He faces a trial in that case in New York next year.
Additional reporting by Madeline Halpert