Two men who were among four people killed when gunmen fired into a crowd of 100 or more people were gang members killed by two rival gangs, police said Sunday.

The two men killed in the Friday shooting, Kendrick L. Jackson, 34, and Jacoby E. Claybrooks, 28, were members of a resurrected Chicago gang that has killed about 24 people over the past decade, police chief Edward Flynn said.

Two women killed in the shootings, Theresa Raddle, 23, and Marielle Fisher, 27, were apparently innocent bystanders, Flynn said. Two others were injured in the shootings.

Police have not named any suspects, but Flynn said investigators believe two rival gangs carried out the shootings. Police believe there were multiple shooters because bullet casings from multiple guns were found, he said.

The gang the two slain men allegedly belonged to came to Milwaukee in the late 1990s and is aggressively trying to take over the local drug trade, Flynn said.

He said officers would begin patrolling streets daily, a move he hopes will embolden residents who resist cooperating with police out of fear of gang retaliation.

Milwaukee Mayor Tom Barrett said community members need to step forward, even if that means turning in a family member.