It's being called the largest security operation in Canadian history. Police are preparing for the Summit of the Americas in Quebec City, where 34 heads of state from North, Central and South America will gather in April to talk about globalization and free trade.

Police are bracing themselves for thousands of protesters. Up to 5,000 officers will be on hand for the summit to ensure it isn't disrupted by the kind of violence that rocked Seattle when that city hosted trade talks in 1999.

Quebec City is beginning to look like a fortress. Barbed wire is already up around the historic Plains of Abraham, and by the time the summit begins, it will surround the old city. A water cannon will be on standby. And a local prison will be emptied out to make room for unruly demonstrators.

Those who don't show the proper identification will be shut out of the summit. Even attendees who live in Quebec City have to be registered.

The senior summit co-ordinator makes no apologies for the intense security measures. Marc Lortie blames extremists who've hijacked proceedings in the past.

The recent international meetings that took place demonstrated we have to be well prepared, said Lortie.

Lortie wouldn't confirm reports that the security cost forthe summit sits at $30 million.