MILWAUKEE (AP) — At least one person fired a gun into a crowd in a street early Friday, killing four people and sending panicked revelers running for cover, police said.

Two women, ages 23 and 27, and two men, ages 24 and 28, were killed at about 2:30 a.m. on the city's north side, police spokeswoman Anne E. Schwartz said. Two people were injured.

More than 100 people were on the street when shots were fired, some possibly from a party, Schwartz said.

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