French troops are out in force around Paris's river Seine, equipped with everything from drones to dogs, as the countdown to the riverside Olympic Games opening ceremony ticks towards zero.
Soldiers have "tried to plan for every eventuality" in the four-by-two-kilometre (2.5 by 1.2 miles) zone where 10,000 athletes will stage a waterborne parade on July 26, a senior officer told reporters.
He gave only his first name, Olivier, under French army rules for speaking to the press.
The 800-strong deployment has to contend with a dense urban environment where threats could appear by water or from the air.
And last weekend's narrowly failed assassination attempt on US presidential candidate Donald Trump recalls that any major event is subject to risk of attack.
"It's a complex and unprecedented mission", the officer said, vowing that troops will "adapt to any changes and any evolution of the threat."
Among the soldiers are combat divers, boats, intelligence gathering units with drones, canine teams and troops equipped with anti-drone weapons.
The troops showed reporters high-tech equipment including a "jamming rifle" designed to block the signals of hostile unmanned aircraft, or a diver's gun that can be fired underwater.
Some reporters were brought aboard an engineering boat for a mock patrol above a riverbed sown with sonar detectors.
On board were Foreign Legion infantrymen equipped "with all the weapons systems allowing them to intervene, especially in case of a terrorist threat," said the boat's captain, who gave his name as Quentin.
The pilot gunned the engine hard as Quentin explained that the soldiers can get from one bank to the other "in just a few seconds" to respond to an incident.
Thursday will see the full activation of the protected zone around the Seine, with only authorised boats allowed to enter.
A water barrier has been set up in eastern Paris near the Austerlitz railway station with a gate that can be opened and shut.
Its surface nets leave the waterway below open to give free rein to the Seine's current as long as there is no threat, said military engineer Carl, wearing an arm patch with the security operation's logo of blue, white and red rings recalling the Olympic insignia.
Another net can be dropped to the bottom of the river within seconds to completely block off underwater attacks, he added.
On the embankments, soldiers trained with fast-moving off-the-shelf Parrot Anafi drones.
The quadcopters are fitted with infrared cameras and high-performance zoom to spot threats.
Drones are there at once to "survey, clear suspicions, and also as dissuasion," said a soldier.
"If the opening ceremony is successful, we'll be in good shape to earn the confidence of the French public and Parisians for the rest of the Games," the senior officer said.
