U.S. Attorney General Merrick Garland speaks about the FBI's search warrant served at the home of former President Donald Trump in Washington

U.S. Attorney General Merrick Garland confirmed on Thursday that federal agents had searched former President Donald Trump's Florida estate to probe whether he illegally removed records from the White House as he was leaving office.

Garland, the nation's top law enforcement official, said he had personally approved the decision to search Trump's home.

He said the Justice Department had asked a court to unseal a search warrant filed as part of the investigation due to "substantial public interest," after Trump himself announced the search in a statement on Monday night.

The unprecedented search at Trump's Mar-a-Lago resort in Palm Beach marked a significant escalation in one of the many probes he is facing from his time in office and in private business.

Garland's Justice Department has faced fierce criticism and online threats this week following the search. Trump supporters, and some of his fellow Republicans in Washington, have accused Democrats of weaponizing the federal bureaucracy to target Trump.

The FBI said an armed person had tried to breach its office in Cincinnati early on Thursday in what it called a "critical incident." Local law enforcement said officers traded shots with a male suspect wearing body armor.

Garland condemned the attacks on employees of the FBI and Justice Department. "I will not stand by silently when their integrity is unfairly attacked," he said.

Former U.S. President Donald Trump  departs Trump Tower for a deposition two days after FBI agents raided his Mar-a-Lago Palm Beach home