At 10:25 a.m., the robber entered the bank at 9 Northern Blvd. and gave a note to the teller demanding money. In the note, the man claimed to have a gun; he did not display a weapon, police said.
After receiving an unknown amount of cash, the robber fled on foot, heading north through the parking lot.
No one was injured in the robbery. Five employees and a customer were in the bank at the time, police said.
Police describe the robber as a 6-feet, 2-inch tall man, about 40 years old, with a medium complexion, wearing camouflage shorts, a black T-shirt, white sneakers and a fedora hat.
Detectives are asking anyone with information to call Nassau County Crime Stoppers at 800-244-8477. All calls are anonymous.