Mystic — The Captain Daniel Packer Inne, an 18th-century landmark, was evacuated Wednesday night after fire broke out under the kitchen, according to Mystic Fire Chief Fritz Hilbert.

The restaurant's staff called for help after the kitchen and dining area filled with smoke around 7:30 p.m., and about 50 people fled the building, Hilbert said. There were no injuries.

With some difficulty, firefighters traced the source of the fire to a space heater in a crawl space under the kitchen that is used to keep pipes from freezing.

Damage to the building, which was built in 1756, was minimal, and the restaurant may be able to reopen as soon as Thursday, Hilbert said. First, it will be inspected by the Groton building official and the Ledge Light Health District.

About 20 members of the Mystic Fire Department extinguished the fire without mutual aid.

The building, which remained in the hands of the Packer and Keeler families from the 18th century until the late 1970s, underwent a four-year renovation starting in 1979, according to the restaurant's website. Hilbert said there have been several minor fires over the years but no major ones.

"It's still standing, so thank God," Hilbert said.

The fire remains under investigation.