Investigators are working to determine what caused a two-alarm fire at a vacant building in New London late Tuesday night.

Firefighters said they responded to a fire at a vacant, three-story brick building on Trumbull Street in Fort Trumbull shortly after 11 p.m.

Crews were able to knock down the main body of the fire, but remained on scene until early Wednesday morning.

BREAKING: #NewLondon Fire Marshal confirms second alarm fire in vacant 3-story brick building at 100 Trumbull Street in #FortTrumbull. Main body of fire knocked down but firefighters will spend night overhauling. Investigation underway. Video: Steven Frischling #nbcct @Local1522 pic.twitter.com/SSwuL6EY9W — Heather Burian (@HeatherBurian) March 13, 2019

A fire boat was called in because one side of the building abutted the water, but firefighters did not need to use it, fire officials said.

No injuries were reported, but one boat was damaged.

The cause of the fire is under investigation.