MILWAUKEE (AP) — At least one gunman fired into a crowd of more than 100 people partying in the street early Friday, killing four of them, police said.

Two women, ages 23 and 27, and two men, ages 24 and 28, were killed at about 2:30 a.m., police spokeswoman Anne E. Schwartz said.

A 35-year-old woman and 31-year-old man were hospitalized with injuries that were not believed to be life-threatening. Police were unsure whether the woman was shot or hit by flying glass.

No suspects are in custody. Police were having difficulty getting cooperation from witnesses, Schwartz said.

"We're not getting a lot of help here," Schwartz said.

Police initially said the shooting happened outside a house party.