It shall be unlawful for 3 or more persons to assemble together with intent to do an unlawful act, separately or in concert, with force or violence against any property of the city, or against any person or his or her private property; to act in such a manner as to cause fear or terror to any person; to make any movement, preparation, or demonstration against the peace of the city or against the peace or property of any citizen thereof; for any person present at any such meeting or assembly, by his or her presence or otherwise, to aid, abet, assist, encourage, or countenance the commission of any unlawful act, movement, preparation, or demonstration.
(1975 Code, § 15-30) Penalty, see § 10.99