A. A person commits unlawful assembly by:
1. Assembling with two or more other persons with the intent to engage in conduct constituting a riot as defined in section 13-2903; or
2. Being present at an assembly of two or more other persons who are engaged in or who have the readily apparent intent to engage in conduct constituting a riot as defined in section 13-2903 and knowingly remaining there and refusing to obey an official order to disperse.
B. Unlawful assembly is a class 1 misdemeanor.