STOCKTON (CBS13) – A large fire damaged an apartment complex undergoing a remodel in Stockton late Tuesday night.

The incident happened at the Sierra Vista Apartments along 11th Street. Firefighters say they responded around 11 p.m. and found that a very large fire had broken out at the construction site.

Firefighters say it was initially difficult to get to the flames, as the fire was coming from the middle of the complex. Crews had to work fast to try and keep the flames from spreading to other buildings. Civilians even jumped in to help pulling hoses.

Several units were burned in the fire. However, firefighters say their efforts saved millions of dollars in further damage.

Exactly what caused the fire is still under investigation.