Updated

For all the talk of surveillance cameras, radiation detectors and other high-tech devices, security at the Republican National Convention (search) on Monday boiled down to warm bodies — in uniform, heavily armed and omnipresent.

Packs of police officers stood guard on streets and subways around Madison Square Garden (search) in a massive show of force expected to continue throughout the four-day event.

The armed camp in midtown Manhattan delighted some delegates.

"New York City is a fortress and I love it," New Jersey state GOP Chairman Joseph Kyrillos announced Monday at a delegate breakfast. "We need to thank the New York City police for all the protection."

If delegates wanted to offer thanks, they didn't have to look far: Up to 10,000 officers have been deployed by the 36,500-member New York Police Department. That contingent has teamed with federal and state officers to form what some say is the largest security force ever assembled in the city.

Last week, Madison Square Garden, was put under constant surveillance by security cameras, rooftop marksmen and police helicopters. A strike force of plainclothes officers on scooters stand ready to chase down troublemakers.

Buses shuttling delegates from their hotels to the arena pass through checkpoints fortified by hydraulic metal barriers. All vehicles are screened for bombs and other contraband by cameras that provide real-time video images of the undercarriages. Dump trucks filled with sand block normal traffic from the restricted zone.

"I knew security would be tight, but I was surprised at how tight it was," said Tre Hargett, a delegate from Memphis, Tenn.

The NYPD has been preparing for more than a year. Many officers received response training for chemical, biological and radiological attacks at a cost of millions of dollars. The NYPD's intelligence division has studied the March bombings in Madrid, which killed 190 people in the days leading up to an election, as a possible template for an attack during the convention and beyond.

"We have the resources, and we're going to use those resources to keep the city safe, and to keep the convention safe," said Police Commissioner Raymond Kelly.

Thousands of officers helped keep order Sunday at an anti-war protest. About 200 demonstrators were arrested.

"I think we showed that we're prepared, we're flexible, we're mobile and we're going to make the appropriate arrests," Kelly said.

On Monday, commuters at Penn Station were greeted by officers posted every few feet, many with bomb-sniffing dogs.

At the convention, Secret Service agents and plainclothes police officers checked credentials. All bags and briefcases were searched.

"The security is just like in airports," said Brenda Neal, a delegate from Blacksburg, S.C. "It makes me feel very safe."