Va. Code Ann. § 18.2-406

Whenever three or more persons assembled share the common intent to advance some lawful or unlawful purpose by the commission of an act or acts of unlawful force or violence likely to jeopardize seriously public safety, peace or order, and the assembly actually tends to inspire persons of ordinary courage with well-grounded fear of serious and immediate breaches of public safety, peace or order, then such assembly is an unlawful assembly. Every person who participates in any unlawful assembly shall be guilty of a Class 1 misdemeanor. If any such person carried, at the time of his participation in an unlawful assembly, any firearm or other deadly or dangerous weapon, he shall be guilty of a Class 5 felony.