Describing it as an “attack on a political opponent”, the former US president claimed that agents had “stolen” three of his passports. The FBI searched his home last week after officials discovered boxes containing classified information were moved to his estate after his presidency ended. They were retrieved in January by the National Archives and Records Administration (NARA), which then asked the Justice Department to investigate whether Trump’s handling of White House records violated federal law. In a post on Truth Social – his own social media platform – Mr Trump told his followers: “Wow. In the Mar-a-Lago FBI raid, my three passports were stolen (one was expired), together with everything else. “This is an attack on a political opponent on a level never seen before in our country. Third world.” A Justice Department official told NBC News that Mr. Trump’s passports were not in the FBI’s possession and had in fact been returned to the former president. Trump supporters have been largely galvanized by the investigation, rallying around him and criticizing the move as political as it comes at a time when many expect him to announce plans to run for another term. Use Chrome browser for more accessible video player 1:51 Why was Donald Trump’s property raided by the FBI? “The temperature must drop” Speaking on Fox News Digital, Mr Trump warned that “terrible things are going to happen” if frustrations are not eased. “The country is in a very dangerous place. There is tremendous anger like I’ve never seen before, about all the fraud and this new one — years of fraud and witch hunts, and now this,” Trump said. “People are so angry about what’s going on,” he added. “Whatever we can do to help – because the temperature needs to drop in the country.” He went on to say that the FBI “could have planted whatever they wanted” during the investigation. “There has never been a time like this where law enforcement has been used to raid the home of a former president of the United States, and there is tremendous anger in the country — at a level never seen before, except in very dangerous times,” he said. Image: Aerial view of Donald Trump’s Mar-a-Lago home The underlying affidavit could be unsealed During the raid, officers discovered more than 20 boxes of items, some of which were classified as top secret. A search warrant showed that agents recovered a set of documents that were marked not only as top secret but also as “sensitive apartment information,” a special category intended to protect the nation’s most important secrets. A binder of photographs, a handwritten note and information about the “President of France” were also seized. Use Chrome browser for more accessible video player 0:44 Trump is being investigated over espionage allegations Read more: Why did the FBI raid Donald Trump’s property – and what are they investigating? ‘I Approve Trump FBI Search Warrant’ The warrant also revealed that Trump is being investigated under the Espionage Act. Members of the US media have asked the Justice Department to unseal the affidavit prosecutors used to get a federal judge’s approval to search Trump’s Florida home. On Monday, the ministry said it had objected to the requests because the investigation “contains highly classified material” and the document contains sensitive witness information. The document would have revealed the evidence prosecutors showed to show they had probable cause to believe crimes were committed.