A Secret Service laptop containing floor plans for Trump Tower has been stolen from an agency vehicle in New York.
Authorities are still looking for the device, which is encrypted, the New York Daily News reported.
It was also said to contain details of the investigation into former Democratic Presidential candidate Hillary Clinton's use of a private email server.
The Daily News cited police sources and said the thief stepped out of a car in a Brooklyn street before stealing the laptop from an agent's vehicle.
According to ABC, authorities are able to wipe the laptop's hard drive remotely if necessary. They are reportedly using video evidence in an attempt to identify the thief.
The Secret Service said in a statement: "The US Secret Service can confirm that an employee was the victim of a criminal act in which our agency issued laptop computer was stolen.
"Secret Service-issued laptops contain multiple layers of security including full disk encryption and are not permitted to contain classified information."
It declined to comment further "until the facts are gathered".