A man armed with an assault rifle held up a Subway Sandwich shop in Sonoma Saturday night and made off with an undisclosed amount of cash from the register.

A clerk told authorities that a white male in his 30s entered the shop at 927 Broadway shortly before 8:40 p.m. and pulled out out a rifle concealed in his black coat.

The robber pointed the weapon at the clerk and demanded all the money from the register, Sgt. Spencer Crum said in a release issued by the Sonoma County Sheriff's Office.

After the clerk emptied the register and handed over the contents, the suspect demanded money from the safe. When the clerk said he didn't have the combination, the suspect ordered him to the ground and fled out the back door with the cash from the till.

Authorities said the suspect is of medium build with brown, unshaven facial hair. Anyone with information regarding the case is asked to contact the Sonoma Police Department at 996-3602.