Police are evacuating tourists and others from France’s Mont-Saint-Michel abbey and monument after a visitor apparently threatened to attack security services., the Express reported on Sunday.
The national gendarme service said the man had made the threat while travelling on a shuttle serving the site in Normandy.
A witness heard a man uttering threats after he entered the site in the northwestern region of Normandy.
An official said the threat was vague, but sufficient to order an evacuation at about 5.30am GMT.
District prefect Jean-Marc Sabathe told France Info radio station: "For security reasons and in order to clear up any doubt, since we don't know his aim, I've decided to evacuate the Mont."
The shuttle service official said large numbers of people were being evacuated or turned away with a police helicopter is overhead, although the mood was calm with no sense of panic.
Mont-Saint-Michel, which is located on a island just off the coast of Normandy in the English channel, is one of the most visited historic sites in France, with several thousand tourists a day.
According to the Ouest-France newspaper, the individual allegedly wanted to "kill police" and escaped before authorities arrived.
Broadcaster France Info quoted a gendarmerie as saying: "An individual has entered Mont-Saint-Michel. He made fairly specific threats against the police in front of a coffee shop," the gendarmerie told broadcaster France Info.
A local journalist, Denis Surfys, tweeted: “The gendarmes are tracking down an individual.
“Total evacuation and total blocking of the site.”