King Charles and Queen Camilla were rushed to safety after their security team spotted a figure on a nearby roof during an open-air event in Jersey, according to reports.
The monarchs were escorted to a local hotel as a precautionary measure following the security alert on Monday.
This incident came just hours after former US President Donald Trump was shot at a rally in Butler, Pennsylvania. Mr Trump sustained an ear injury in the attack, which took place on Saturday.
The alleged assailant, identified as 20-year-old Thomas Matthew Crooks, was fatally shot by security services at the scene.
The King and Queen were in Liberation Square, St Helier, and greeting well-wishers when a bodyguard was heard to say “he has to go now”.
The Jersey suspect was allegedly challenged by police but no action was taken after a background check.
Local police later confirmed it had been a false alarm.
Charles and Camilla are visiting the Channel islands of Jersey and Guernsey this week.
The King is said to have written to Mr Trump after the assassination attempt. The royal was himself fired at with a round of blanks while visiting Sydney in 1994.
Ken Wharfe, a former Royal Protection Officer, said: “Had there not been an incident involving Donald Trump, this would probably have gone unnoticed and maybe action would have been different.
“But the very fact there were criticisms of the Secret Service and police because there was a rooftop problem with Donald Trump, under the circumstances, I would have probably done the same.
“Had this man been found with something dangerous and they hadn’t taken them out of the pitch, they would be roundly criticised.
"Their immediate assessment was correct.”
