“We can do it and we will do it,” Macron told France’s RMC Radio and BFM TV on Monday morning. “If we think there are security risks we’ll have plan Bs, and even plan Cs,” he added.

He said that one of those alternatives could be to hold the ceremony in the Trocadero Square facing the Eiffel Tower, where the river route culminates. The plan is already for the final elements of the event to happen here.

Another option is to move it to a more traditional sports stadium setting in the Stade de France, the national arena to the north of Paris that is due to host track & field events.

Crowds of 300,000 spectators are expected along the Seine to try and grab a glimpse of the ceremony, with dozens of giant screens to relay the action. Those plans were scaled back from initial ambitions for some 600,000 riverside spectators, most of them free tickets.

Authorities in Paris will use pioneering surveillance technology to monitor possible threats, with plans to deploy SWAT teams where necessary.

The security operation in Paris is so vast that other countries are helping.

Poland is among the 46 nations to add its military personnel to French operation, which itself is bolstered by 18,000 French soldiers.

Speaking earlier this month, Macron told journalists that he had no doubt that Russia would target the games in some way.

“I have no doubt, I have no doubt, including in informational terms. Every day, it [Russia] fuels rumors about the fact that we could not do this or that, so it would be a risk,” he said at the inauguration of an Olympic swimming pool near Paris.

Beyond security, the Olympics are also contending with worries about the Seine’s suitability for some swimming events. But Macron set aside worries about pollution levels, saying Monday that he still planned to take a dip in the river before the Games begin.

His interview came a day before the Olympic flame will be lit at a ceremony in Olympia, Greece, setting off a relay before its arrival in Paris for the opening ceremony.