NEW YORK —  Radical protesters are reportedly trying to cause chaos at the Republican National Convention (search) in New York City at the end of August.

Reports show that fringe groups are hatching a plot on the Internet, telling people how to attack and trick police with the ultimate goal of evacuating Madison Square Garden (search). The suggestions include everything from throwing marbles in the path of police-mounted horses to going to shooting ranges before heading to the convention so that their clothes will reek of gunpowder and trick bomb-sniffing dogs on the subways and commuter trains.

New York City police (search) say they are worried about the tactics diverting their time and resources from preventing authentic attacks, and add that they are preparing for "black blocs" of anarchists who cover their face with bandanas and vandalize corporate targets. 

Click on the video box at the top of this story to watch a complete report by FOX News' Rebecca Gomez.