DENVER -- The Denver City Council has passed an ordinance barring protesters from carrying buckets of feces during the Democratic National Convention.

Three protest groups say they've already promised not to toss, smear or spray feces, and they call the new ordinance insulting and excessive.

The council approved the ordinance 12-0 on Monday. It also bars protesters from possessing chains, locks or other materials they could use to create human barricades or cause other disruptions.

Members of Re-create 68, Unconventional Action and Tent State University say the ordinance is overkill because they have signed an agreement not to use excrement.

The convention will be Aug. 25 to 28 in Denver, culminating with the acceptance speech of Barack Obama at Invesco Field at Mile High Stadium. The procedure to secure tickets for that event is expected to be announced Wednesday.