Police report four arrests in connection with a disturbance on the street outside The Keg of Evanston shortly after the bar's 3 a.m. closing time Saturday.
Deputy Chief Joe Bellino says several fights broke out as 150 to 200 patrons poured out of the bar at 810 Grove St., and "there were shouts between two combative groups signifying their street gang affiliation."
Evanston police called in Wilmette and Northwestern University officers to help quell the disturbance.
While the fighting was underway, a 27-year-old passerby reported he was struck in the face by a man when he asked him what was going on.
Police have charged 24-year-old Ryan Irving of 1309 Simpson St. with battery in connection with the attack on the passer-by.
They've filed disorderly conduct charges against three other men: William Norman, 22, of 1722 Grey; Maurice Jackson, 23, of 9126 Keating in Skokie, and Kelvin Nails, 22, of 809 Mansfield Ct. in Schaumburg.
Evanston police say Norman may also face charges from Northwestern University police regarding damage to a university squad car at the scene of the disturbance.