US President Joe Biden denounced threats received by FBI agents after they searched the home of former President Donald Trump in Florida on August 8, in a precedent in the history of former US presidents.

"It is disgusting to see the new attacks on the FBI, and the threat to the lives of law enforcement officers and their families just because they are law enforcement and doing their job," Biden said in a speech Tuesday at a conference in Pennsylvania.

"I would like to say it as clearly as I can. There is no place in this country, there is no place to threaten the lives of law enforcers."

The US president stressed that he opposes withholding government funds from the police and the FBI as well.

The FBI and the Department of Homeland Security warned of increased threats in the wake of the raid on Trump's home, as investigators seized what were described as 11 sets of classified documents, some of them classified as "top secret", as part of an ongoing criminal investigation.