Fire engulfed an unoccupied multiunit oceanfront residence in the Village of Westhampton Beach on Wednesday.
"I believe the entire property is lost," Mayor Maria Moore said.
She said Westhampton Beach firefighters were able to stop the flames at The Sandpiper on Dune Road from spreading to other buildings.
"We have a lot of help from other fire departments with mutual aid," the mayor said.
She said the facility had not yet opened for the season and only maintenance workers were on the property at the time.
Moore said she had heard no reports of injuries. The fire call came in at 3:06 p.m., she said. Multiple fire departments responded to The Sandpiper, a seasonal co-op with about 60 mostly one-bedroom units.
Photos from the scene showed the fire engulfing nearly the entire structure.
Westhampton Beach police and fire officials said they could not immediately comment.