Former U.S. President Donald Trump said FBI agents raided his Mar-a-Lago estate on Monday and broke into his safe in what his son acknowledged was part of an investigation into Trump's removal of official presidential records from the White House to his Florida resort.

The unprecedented search of a former president's home would mark a significant escalation into the records investigation, which is one of several probes Trump is facing from his time in office and in private business.

The U.S. Justice Department declined to comment on the search, which Trump in a statement called a raid and said involved a "large group of FBI agents." The FBI's headquarters in Washington and its field office in Miami both declined comment.