A possibly armed bank robber remains on the loose Thursday, following a brazen mid-afternoon heist at one of San Francisco's most prominent banks.

It was 3:20 Wednesday afternoon, police say, when a man in his 20s entered the Wells Fargo Bank at 1 California Street.

Once inside, according to the San Francisco Police Department, he approached a 22-year-old male employee of the financial institution, and announced his intentions to rob the place.

The suspect "acted like he had a gun," according to the SFPD, and told the teller "that if he did not comply, [the robber] would shoot him."

Though "no gun was seen," during the heist, the teller quite reasonably complied with the robber's demands, handing over an undisclosed amount of cash.

The thief fled on foot, and remains at large. As of Thursday morning, no additional details were available regarding the suspect, but police confirm that no arrests have been made in the case.