Former US President Donald Trump said Monday that his Mar-A-Lago residence in Florida was being "raided" by FBI agents in what he called an act of "prosecutorial misconduct".

The FBI declined to comment on whether the search was happening or what it might be for, and Trump did not indicate why federal agents were at his home.

"These are dark times for our Nation, as my beautiful home, Mar-A-Lago in Palm Beach, Florida, is currently under siege, raided, and occupied by a large group of FBI agents," Trump said in a statement posted on his Truth Social network.

Aerial footage of Mar-a-Lago showed police cars outside the property.

"It is prosecutorial misconduct, the weaponization of the Justice System, and an attack by Radical Left Democrats who desperately don't want me to run for President in 2024," said the former president, who was not present during the raid, according to The New York Times.

"Such an assault could only take place in broken, Third-World Countries. Sadly, America has now become one of those Countries," Trump said, adding: "They even broke into my safe!"

Multiple US media outlets cited sources close to the investigation as saying that agents were conducting a court-authorized search related to the potential mishandling of classified documents that had been sent to Mar-a-Lago.

The National Archives said in February it had recovered 15 boxes of documents from Trump's Florida estate, which The Washington Post reported included highly classified texts, taken with him when he left Washington following his reelection defeat.

The documents and mementos - which also included correspondence from ex-US President Barack Obama - should by law have been turned over at the end of Trump's presidency but instead ended up at his Mar-a-Lago resort.

The recovery of the boxes raised questions about Trump's adherence to presidential records laws enacted after the 1970s Watergate scandal that require Oval Office occupants to preserve records related to administration activity.

The Archives had requested then that the Justice Department open a probe into Trump's practices.

White House staff also regularly discovered piles of paper clogging toilets, leading them to believe Trump was trying to get rid of certain documents, according to a forthcoming book by New York Times reporter Maggie Haberman.

Read more: Trump says Pelosi’s Taiwan visit 'will only make it worse'