SAN LEANDRO -- Police are investigating an armed robbery at an outdoor ATM at a bank on Marina Boulevard before sunrise Friday.

At 5 a.m., a customer was using the ATM machine at the Wells Fargo Bank at 1899 Marina Blvd., in San Leandro when he was approached by a man armed with a gun and wearing a dark colored hooded sweatshirt pulled over his face. The man was robbed of an undisclosed amount of cash, police said. He was not injured.

Lt. Robert McManus said detectives are working with Wells Fargo security agents and nearby merchants, trying to locate video surveillance that could help identify the suspect.

"We want to remind everyone to always be aware of their surroundings, especially while using ATM machines. We recommend the use of outdoor ATM machines during daylight hours if possible, or when the area has others around, as this generally deters crimes like this," McManus said.

A full description of the suspect was not available. The man ran away from the ATM and a getaway car was not seen.

Anyone with information regarding this case should call 510-577-3230 or contact the anonymous tip line at 510-577-3278.

Reach Kristin J. Bender at kbender@bayareanewsgroup.com. Follow her at Twitter.com/kjbender.