Aerial footage from the scene showed a large plume of smoke as fire-fighting boats shot water into structure.
OCEANSIDE, Calif. (KABC) -- Firefighters in Oceanside are battling a massive blaze that broke out at a former Ruby's Diner on the city's historic pier.
The fire was reported just after 3 p.m. Thursday.
According to officials, the fire started in a vacant building at the western end of the pier. The Ruby's Diner shut down three years ago.
Aerial footage from the scene showed a large plume of smoke as fire-fighting boats shot water into structure. You could also see flames burning inside the building on an adjacent section of deck.
There's been no word of any injuries. The cause of the fire remains under investigation.
The Oceanside Fire Department has asked all residents to avoid the area and to stay away from Pacific and The Strand as first responders work to extinguish the fire.
The pier was originally built in 1888 and has been destroyed twice before. It fell during a storm in 1890 then was rebuilt in 1896, but it was destroyed again in 1902.
A similar incident occurred on the Seal Beach Pier in 2016 when a fire ripped through another former Ruby's Diner building. That fire was caused by an electrical issue.