OAKLAND — Police are looking for two men in connection with a midnight robbery of the Safeway store in Oakland's Rockridge district Friday.

A half-dozen employees and at least one customer were inside the store at 6310 College Ave. when two short, heavy men wearing bandannas over their faces and carrying guns entered at about 12:15 a.m., police said.

They forced at least one employee to open four cash registers before they fled with an unknown amount of cash. No one was hurt during the incident, and nothing was taken directly from the workers or the customer, police said.

The suspects are described as two men in their 20s or 30s. One is about 5-foot-6 and 230 pounds, and the other is 5-foot-4 and roughly 190 pounds. Race could not be determined because of their masks and clothing, police said.

The men jumped into a gold-colored GMC pickup, which last was seen heading north on Claremont Avenue.

Police and CrimeStoppers of Oakland are offering up to $7,500 in reward money for information leading to the robbers' arrests. Call police at 510-238-3326, or CrimeStoppers at 510-777-3211 or its anonymous tip line at 510-777-8572.

In a separate incident earlier that evening, police apprehended four suspects in a series of street robberies. At about 6:30 p.m. Thursday, an Oakland undercover officer driving in the 2700 block of Foothill Boulevard in East Oakland saw four teenage boys surrounding a man on the street and trying to rob him, police said.

Before the robbery could be completed, the officer radioed for additional units, and uniformed officers arrived, taking the four into custody. One boy is 16, two are 15 and one is 14, police said.

While the officers were on the scene, they were approached by another man who told them that the same four teens had robbed him a short time before, at about 5:50 p.m. in the 3100 block of East 27th Street. The man positively identified the four.

Minutes later, yet another man approached the officers and also identified the boys as those who had robbed him at 6:20 p.m. in the 1800 block of 28th Avenue.

The boys are in custody on suspicion of robbery and attempted robbery, police said. One confessed his involvement in the crimes to investigators, one denied involvement and two declined to talk, police said.