The U.S. military responded to a concerning incident near Mar-A-Lago last week.

An F-16 fighter jet performed a "headbutt" maneuver to alert a private pilot who flew too close to the president's private estate. Trump was in Florida at the time for a weekend of golf.

Since Trump's inauguration on January 20, there have been more than 20 incidents of pilots violating the restricted airspace over his Florida resort.

Mar-A-Lago incident

The Air Force issued a statement on the latest incident, which took place before 11 a.m. on Friday, April 4.

A North American Aerospace Defense Command (NORAD) F-16 left Tyndall Air Base to intercept a civilian aircraft. The fighter jet performed a maneuver, known as a headbutt, to get the pilot's attention.

"The civilian aircraft violated the Temporary Flight Restriction (TFR) at approximately 10:50 a.m. Eastern Daylight Time. NORAD aircraft conducted a headbutt maneuver to gain the civilian pilot's attention, and the aircraft was safely escorted out of the area," the statement from NORAD said.

“NORAD and the FAA work closely together to keep the skies over America safe, with close attention paid to areas with Temporary Flight Restrictions (TFR),’’ said Gen. Gregory Guillot, Commander, NORAD and U.S. Northern Command.  “Adherence to TFR procedures is essential to ensure flight safety, national security, and the security of the President.”

A headbutt is when a fighter jet flies in front of another plane to draw their attention. The maneuver is sometimes used to warn adversaries or, less commonly, civilian pilots who fail to respond after entering restricted airspace.

Pilot faces fines

The civilian pilot is facing fines and the loss of his license, local West Palm Beach TV station WPTV reported.

Federal aviation authorities have warned pilots that temporary flight restrictions will be in effect next weekend in West Palm Beach, indicating Trump is returning to Mar-a-Lago.

Often seen as an unofficial White House, Trump regularly visits his opulent Florida estate to enjoy golf and hold court with foreign dignitaries and hangers-on.

Trump faced an assassination attempt in September while playing golf at his golf course in West Palm Beach. The suspect was spotted by the Secret Service and apprehended after a police chase.

The Justice Department has revealed that Ryan Routh tried to buy a rocket launcher from Ukraine in order to shoot down Trump's plane. Routh is facing a trial in September.

“I need equipment so that Trump cannot get elected," Routh allegedly texted a Ukrainian associate.