OAKLAND (CBS/BCN) - One person has been shot dead and six more were hurt - one critically - in separate shootings in Oakland Tuesday night, according to authorities.

In the first instance, police spokesman Jeff Thomason said officers responded to the 2500 block of Market Street at 5:56 p.m. to investigate a shooting and found a man who had been shot.

The victim, 22-year-old Allen Collins, who police said was known to frequent the area, was transported to a hospital where he later died.

A preliminary investigation turned up several leads, but as of 7 a.m. no arrests had been made in the case and the motive was still unclear, Thomason said. 

Later, officers responded to an emergency call at 9:38 p.m. reporting a shooting in the 1100 block of 89^th Avenue, and found two victims who had been shot, Thomason said.

Shortly after police notified local hospitals of the shooting, several other victims with gunshot wounds arrived at a local hospital, Thomason said.

One of the victims sustained life threatening injuries and remains in critical condition.

Four of the victims were adult Oakland residents. Information about the residences of the other two adult victims had not yet been released.

Police continue to investigate the shooting and are searching for the suspects.

Anyone with information on the shootings is asked to contact the Criminal Investigation Division at (510) 238-3426 or homicide investigators at (510) 238-3821.

(© 2011 CBS Broadcasting Inc. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed. Bay City News contributed to this report.)