(CNN) -- Seven people were wounded Monday evening in a shooting on an Oakland, California, sidewalk, police said.
The shooter or shooters approached a group and started firing, said Oakland police spokeswoman Johnna Watson.
Authorities do not have a motive.
The wounded are all men, ranging in ages from 23 to 31. Two of them are in critical condition, she said.
Police hope that witnesses will come forward, so they can piece together what happened.
Residents said a barbeque was being held at the time of the shooting, reported the Oakland Tribune.
"This is really kind of outrageous," Oakland police Chief Sean Whent told the newspaper. "Six o'clock at night isn't that late at night. So, really pretty brazen stuff on the street corner at that time of day."