Investigators are trying to determine what sparked a three-alarm fire Wednesday in a century-old building in Lower Manhattan.

The fire broke out just before 2:30 a.m. at Ryan Maguire's Ale House at 28 Cliff Street.

Officials say the fire started in the bar's basement and made its way up two floors, before it was brought under control just before 5 a.m.

"We've been here for 15 years, we had another little business just a block away, but the landlord demolished that building. Just, we're out of it right now, so this is all we had," said Mena Maguire, the bar's owner.

"A cellar fire is very hazardous to our members -- very low ceilings, confined pace, high heat, a lot of storage down there," said New York Fire Department Deputy Chief James Daly. "They had stored barrels of beer and things like that. So there's a lot of collapse potential, so it's a very tenuous position to be in for the firefighters."

About a dozen residents of apartments above the bar were taken to a nearby hotel by the Red Cross, and several residents in nearly buildings were evacuated due to heavy smoke and risk of carbon monoxide.

"We all went to bed around the same time, like 1 a.m., and then [my neighbor] was woken up by the smoke," said neighbor Adam McCue. "He woke the two of us up and not long after that a firefighter was knocking on the door. The smoke was very thick, you couldn't really see very much -- especially outside, just a wall of smoke."

Four civilians suffered minor injuries.