OAKLAND -- Two construction workers at a Rockridge district home were robbed at gunpoint Monday afternoon, the latest in a series of similar robberies, authorities said.

Neither of the victims, a 30-year-old San Francisco man and a 38-year-old Richmond man, were injured.

The men were working at a house in the 400 block of Clifton Street about 4:30 p.m. Monday when they were confronted by two gunmen who threatened to kill them if they did not hand over their valuables.

The workers gave the robbers cash and cell phones before the suspects fled. Neither victim was injured.

The suspects fled in a maroon Toyota driven by a third suspect.

One of the robbers was described as black, 27 to 30, about 6 feet and 230 pounds with a beard and short hair. He wore a blue jacket and a red, black and white plaid shirt and blue pants. The other suspect had a similar description and wore a white sweater, blue pants and white tennis shoes.

Police believe the same suspects may have robbed three construction workers about three hours earlier in the 1500 block of East 19th Street in East Oakland.

Other robberies the suspects might be linked to happened Nov. 29 on Montell Street off Piedmont Avenue, where six construction workers renovating a house were robbed at gunpoint, and another Nov. 18 in the 4900 block of Webster Street where four house painters were robbed.

Police and Crime Stoppers of Oakland are offering up to $25,000 in reward money for information leading to the robbers' arrest. Anyone with information may call police at 510-238-3326 or Crime Stoppers at 510-777-8572.