US media reports suggest investigation is moving closer to charging former president over materials found at his Florida home.
The notice came from the office of special counsel Jack Smith, ABC, The New York Times, CNN and other news outlets said on Wednesday.
The justice department typically notifies people when they become targets of an investigation to give them an opportunity to present their own evidence before a grand jury. The notification does not necessarily mean they will be charged.
Trump, the frontrunner in the race for the 2024 Republican presidential nomination, pleaded not guilty in April to charges of falsifying business records relating to hush money paid to an adult film star before the 2016 presidential race. He also faces a criminal investigation into alleged efforts to overturn his 2020 election loss.
Trump claims the multiple investigations are politically motivated.
The investigation into the classified documents began in 2021, amid suspicions among federal officials that the former president had not returned all the documents he was supposed to.
In August last year, the FBI found some 13,000 documents, 100 of which were marked classified, in a search of Trump’s Mar-a-Lago estate in Florida, even though one of Trump’s lawyers had previously said that all records with classified markings had been returned.
Trump has defended his retention of the documents, suggesting that he declassified them while he was president. However, Trump has provided no evidence for the claim and the court filings show his lawyers have also not made that argument.
Trump is the first current or former US president to face criminal charges, and his legal woes are growing.
In May, a jury in a civil court in Manhattan ordered Trump to pay $5m in damages for sexually abusing former Elle magazine columnist E Jean Carroll and then defaming her by branding her a liar.