Ron Johnson said he thought Mar-a-Lago was "a pretty safe place" for top-secret documents.
He said he was "not overly concerned" about the possible leaking of sensitive data from the estate.
"It has Secret Service protection," the senator said of Trump's Florida residence.
Wisconsin Sen. Ron Johnson has weighed in on the FBI's search of Mar-a-Lago, saying he was not "overly concerned" about the possibility of top-secret information having been leaked from the documents found at former President Donald Trump's Florida residence.
While speaking to Wisconsin ABC affiliate WISN News on Friday, Johnson was asked if he was concerned about potential national security breaches.
"First of all, I think Mar-a-Lago is a pretty safe place. It has Secret Service protection, sounds like these documents might have been in a safe," Johnson said.
"So no, I'm not overly concerned about some top-secret information getting leaked out," he said.
Johnson, who sits on the Senate's homeland security and foreign relations committees, added that he is "always concerned" about classified documents but thought there was no cause for worry with the documents in Trump's hands.
"Raiding a former president's house, that's just a step that I don't think the Justice Department should have taken," he added.
The FBI took 11 sets of classified documents - some of which were reportedly marked top secret and concerned nuclear weapons - from Mar-a-Lago after executing a search warrant on the property last Monday. A federal court has also unsealed the warrant that allowed agents to search Trump's Florida residence.
In February, the National Archives removed 15 boxes of documents from the property.
The Justice Department is now investigating if Trump broke three federal laws, including the Espionage Act - a law introduced in 1917 that prohibits the sharing of information that could harm the US or aid foreign adversaries - when he took the documents to Mar-a-Lago. Those convicted of violating the act face up to 10 years in jail.
For his part, the former president has not denied a Washington Post report that the FBI searched his Mar-a-Lago home for classified documents that contained nuclear information. Trump has also called for the FBI to return the "boxes of privileged 'attorney-client' material" that were taken from the residence.
Experts told Reuters that Mar-a-Lago presented security challenges as a location for storing sensitive government documents.
"Even just retention of highly classified documents in improper storage - particularly given Mar-a-Lago, the foreign visitors there and others who might have connections with foreign governments and foreign agents - creates a significant national security threat," said former Department of Justice official Mary McCord, per the outlet.
Mar-a-Lago's history of security issues has been long documented. In 2017, guests witnessed Trump openly discussing with then Japanese Prime Minister Shinzo Abe what their response to a North Korean missile test should be.
In 2019, a Chinese woman was apprehended and charged after entering the property. Prosecutors said at the time that the woman, Zhang Yujing, had on her person a thumb drive containing "malicious software."
John Kelly, Trump's former chief of staff, also told The Washington Post that he believed the former president might have brought top-secret documents to Mar-a-Lago because he "didn't believe" in the White House classification system.
"His sense was that the people who are in the intel business are incompetent, and he knew better," Kelly told The Post.