SAN DIEGO -- An unarmed, masked robber believed to be in his 20s robbed a Pacific Beach bank branch Saturday, and escaped with an undisclosed amount of cash, San Diego police said.

The robber walked up to a teller at San Diego National Bank, 1945 Garnet Ave., about 9:30 a.m. and said he wanted money, police Officer Brad Ruff said.

The teller did not see any weapons on the man, but gave him some cash, which he put in a paper bag.

Witnesses saw the robber running south down an alley. A police helicopter helped officers search for the man, but he escaped.

The robber was described as Hispanic, 5 feet-6 inches tall, wearing a black mask over his face, wearing gloves, a blue hooded jacket, jeans, and black sunglasses.