A fire at a downtown Jamestown bar Thursday is under investigation.

City firefighters were dispatched just after 2 a.m. for a fire alarm at Sneakers, 100 Harrison St. Crews found heavy smoke when they arrived and quickly distinguished the blaze.

Sam Salemme, Jamestown Fire battalion chief, said the fire originated in a first-floor storage room. The blaze was contained to the one room, which also sustained smoke and water damage.

Off-duty firefighters were called to assist, and crews were on scene for about an hour. Fire investigators were summoned to the Harrison Street bar and remained there until about 5 a.m., Salemme said.

A message to the Jamestown Police Department wasn’t immediately returned Thursday morning.

The bar reportedly has closed as a result of the fire.

Mary Green, owner of Sneakers, claimed in a post on Facebook that the fire was intentionally set.

“Sneakers will be closed indefinitely due to someone breaking in and setting us on fire,” Green said. “Thanks to the Jamestown Fire Dept the damage was pretty much contained to the downstairs but cleanup will be quite extensive. This fire was deliberately set and came very close to killing all of us that live here. Anyone with info please get in touch with me & I will put you in touch with the investigating people.”

In a follow-up post, Green said it would be a “couple of weeks to get it together.”

Green could not be immediately reached for further comment.