from CNN:
Police used the gas when dozens of marchers — most in their 20s, some chanting “F— the police! F— the police! F— ‘em!” — tried to cross a bridge leading to the Xcel Center convention site after being warned not to.
Minnesota State Public Safety Commissioner Michael Campion estimates 200 arrests at the interstate overpass near on Marion Street in St. Paul, where police used chemical agents and flash grenades to disperse the crowd. full story here
video here: http://www.cnn.com/2008/POLITICS/09/04/rnc.protests/#cnnSTCVideo