Bullets struck six victims between ages 16 and 27, Oakland Police said in a statement. .
"Tonight a joyous occasion at our Lake Merritt was marred by a senseless act of gun violence," Oakland Mayor Libby Schaaf said in a statement, according to the East Bay Times"Police in the area tended to victims, and apprehended two people with firearms near the scene
Witnesses said a group of people were arguing before the shooting, FOX 2 of the Bay Area reported, citing social media sources