The Federal Bureau of Investigation has arrested two South Florida mayors on bribery-related charges. The United States attorney’s office said that Mayor Michael Pizzi of Miami Lakes and Mayor Manuel Marono of Sweetwater were taken into custody Tuesday at their offices. According to prosecutors, Mr. Pizzi and a lobbyist, Richard F. Candia, were involved in a kickback and bribery scheme over federal grants in Miami Lakes and Medley. An indictment claims Mr. Marono and a lobbyist, Jorge L. Forte, were involved in a kickback and bribery scheme over federal grants for Sweetwater, where Mr. Marono has been mayor since 2003. Complaints charge the men with conspiracy to commit extortion. Gov. Rick Scott ordered both mayors suspended.