MANATEE -- When they come to Tampa for the Republican National Convention, the estimated 50,000 visitors will see 3,000 to 4,000 officers dressed in special khaki uniforms, including a force of Manatee County law enforcers.

Although the officers will look like one force, they are actually comprised of roughly 60 agencies across Florida.

Among them will be 19 members of the Bradenton Police Department, Bradenton Police Chief Michael Radzilowski said Tuesday.

The exact number of Manatee sheriff's deputies is being kept secret due to security concerns, said Larry McKinnon, a Hillsborough County Sheriff's Office spokesman.

But McKinnon did say the Manatee sheriff's contribution to the event, which officially begins Monday comprises a "significant contingent" of personnel plus a marine unit.

"Manatee County's marine unit will be assisting the U.S. Coast Guard in protecting waterways," McKinnon said. Federal, state and local law enforcement officers began planning for this event in June 2010, said Hillsborough Sheriff David Gee. The two agencies were the only two Manatee County law enforcement agencies on a list provided by the Tampa Police Department.

"The RNC demands thousands of law enforcement officers to converge on downtown Tampa for a 24-hour-a-day presence," Gee states on the Hillsborough Sheriff's Office website. "Some will be assigned special security details. Some will be responsible for getting the scores of buses and vehicles with delegates and VIPs to and from the Tampa Bay Times Forum. Some will be on the street. Some won't be seen but poised to respond quickly and appropriately to a security situation. These law enforcement officers from dozens of sheriff's offices and police departments across the state must execute a uniform philosophy of crowd management and security."

The 19 being sent from the Bradenton Police Department have trained for, and will be utilized as, a riot prevention force in the case of civil disobedience among protesters, Radzilowski said.

"We are sending three squads and a lieutenant," Radzilowski said. "We are a response team for civil disobedience."

Radzilowski was in command of a special operations team in April 2000 in Washington D.C. when an estimated 10,000 demonstrators packed the nation's capital to protest the joint meeting of the World Bank and International Monetary Fund.

"We had three days of violent demonstrations," Radzilowski said.

"We have to be prepared," Radzilowski said. "You do have a contingent of people who don't want to just protest, they want to do mayhem. You could have 200 to 300 showing up on bicycles to disrupt bridges. In D.C., we had people rent school buses to block bridges."

Police have been preparing for the event for nearly two years. Tampa Police Chief Jane Castor said she's studied other protests surrounding political events, most notably the RNC in St. Paul in 2008, where authorities were taken by surprise by an active minority of demonstrators who smashed cars, punctured tires and threw bottles in a confrontation with pepper-spray-wielding police. Hundreds were arrested over a few days, including dozens of journalists.

Castor said she is determined not to preside over a repeat of St. Paul.

Congress has given Tampa and Charlotte, N.C., the location of the Democratic National Convention $50 million each in taxpayer money to try to ensure everyone's safety during the political gatherings that crown each party's presidential candidate every four years.

Tampa police have spent about $13.6 million so far on big-ticket security items, including 200 bicycles, 13 electric all-terrain vehicles and one armored truck.

The city said it has tried to accommodate protesters by creating protest zones and parade routes for those wishing to express their opinions, and officials have met with protesters and held meetings with the American Civil Liberties Union over the past several months.

"The vast majority of individuals coming to the Tampa Bay area to demonstrate will do it peacefully," Castor said.But on Tuesday, police confiscated pipes, bricks and other "suspicious" items from the rooftop of a downtown building located about a mile from where the GOP convention will be held.

Castor said she believes the items were put there by protesters for use during demonstrations next week. She added that some RNC-related graffiti was also found at the building, but wouldn't elaborate.

-- Material from The Associated Press was used in this report.