A security incident at Donald Trump’s Mar-a-Lago resort Monday night has triggered a criminal investigation by the Secret Service in conjunction with the Palm Beach Police Department.

A police department spokesman revealed to reporters early Tuesday afternoon that an “open and active criminal investigation” is underway related to an incident that occurred Monday night and that no arrests have been made, but declined to provide further details. However, the department did provide what The Miami Herald describes as “a nearly completely redacted incident report showing officers were called around 7 p.m. to ‘assist’ another law enforcement agency.”

The Herald provides scant details on the case, only that it is a joint criminal investigation and that the “unspecified” incident took place around 7 p.m. “Michael Ogrodnick, a police spokesman, declined further comment Tuesday, citing the investigation,” the outlet reports. “But the department did provide a nearly completely redacted incident report showing officers were called around 7 p.m. to ‘assist’ another law enforcement agency. The Secret Service did not immediately respond to a request for comment.”

Trump’s resort has been on heightened security in recent weeks after a series of security breaches, some of which have made national news. The property, which Trump has jokingly referred to as “The Southern White House,” has reportedly tightened security even more over the last few days as a result of the president ordering a strategic airstrike that killed Iran’s top military leader, Qassem Soleimani, the head of the Iranian Revolutionary Guard Corps-Quds Force, a U.S.-designated Foreign Terrorist Organization.