Click photo to enlarge
An Oakland police officer walks past evidence markers at the scene of a multiple shooting in which at least seven people were injured, some seriously, Monday, Nov. 25, 2013, at the intersection of 96th and Olive avenues in east Oakland, Calif. (D. Ross Cameron/Bay Area News Group)

OAKLAND -- Seven people, including a man celebrating his 29th birthday, were wounded when at least two gunmen opened fire on a barbecue party Monday evening in East Oakland, police said Tuesday.

No arrests have been made and no motive is known yet for the shooting, which happened about 6:10 p.m. on 96th Avenue near Olive Street.

Two of the victims on Monday night were in critical condition, but one was upgraded to stable condition by Tuesday morning, police said.

All seven shot were men, six of whom live in Oakland, and are expected to recover from their injuries. One of the men hit by gunfire was a 29-year-old celebrating his birthday, authorities said.

Oakland police officers confer and gather evidence at the scene of a multiple shooting in which at least seven people were injured, some seriously, Monday,
Oakland police officers confer and gather evidence at the scene of a multiple shooting in which at least seven people were injured, some seriously, Monday, Nov. 25, 2013 at the intersection of 96th and Olive avenues in east Oakland, Calif. (D. Ross Cameron/Bay Area News Group)

Another 29-year-old man, who was not at the party but lived nearby, was also wounded apparently by an errant bullet, authorities said. Some of the victims were taken to hospitals by ambulance while others got other transportation.

Oakland police Chief Sean Whent said Monday night that it was possible that several people who were hit by the gunfire were not targeted in the shooting, and police were unclear whether the shooters were on foot. Investigators have not ruled out the possibility that the incident was gang-related.

About a dozen people were outside at the time of the shooting, as residents reported a barbecue as being held on the street in part to celebrate the 29-year-old man's birthday.

Some parked vehicles were also hit by gunfire and police were trying to determine Tuesday if any homes in the area were struck.

Police and CrimeStoppers of Oakland are offering up to $35,000 in reward money for information leading to the arrest of suspects. Anyone with information may contact Oakland police at 510-238-3821 or the anonymous tip line at 510-773-2508.

Staff Writer David DeBolt contributed to this report.