A fire broke out underneath the posh Waldorf-Astoria hotel this afternoon, forcing employees and some guests to evacuate, authorities said.

The blaze erupted at 3:41 p.m. in the sub-basement level of the famed hotel along Lexington Avenue near 50th Street, fire officials said.

The FDNY said the fire appeared to have come from a transformer near a garbage compactor that is housed under the hotel.

The fire was extinguished at 5 p.m. by about 80 firefighters.

Some guests did self-evacuate, although the FDNY did not force anyone to leave the hotel.

Fire officials said three people suffered minor injuries. They were taken to Cornell Medical Center for smoke inhalation.