NASHUA - More than 20 people are homeless after a three-story apartment building on Palm Street burned Saturday.

The building, at the corner of Palm and Buck streets, is owned by the Nashua Soup Kitchen.

John Fisher, a member of the Board of Directors with the Nashua Soup Kitchen and Shelter, said the building housed nine apartment units and more than 20 occupants.

"We own the building, which is used as affordable housing and transitional living," Fisher said just minutes after learning about the blaze on Saturday evening. "I'm very concerned. It is currently uninhabitable, and we are working now to make sure that all of the residents have a place to stay."

Some of the occupants are long-term residents of the building, while others are new to the site, according to Fisher, who confirmed that children also reside in some of the units.

"The back of the building was most heavily damaged by fire," said Fisher.

There were three apartments in the rear of the facility. One of the apartment units had just been refurbished and was not yet occupied, he said.

The fire appears to have started outside the building and was making its way up through the apartment house when fire crews responded, Gerhard said. As the fire worked its way up through the building, and onto an adjacent building, fire crews were getting people out and away from danger, he said.

The fire eventually required a three-alarm call, bringing out all on-duty nashua fire crews and equipment, as well as mutual aid assistance from Merrimack, Hudson, Londonderry, Manchester, Windham, and Tyngsboro, MA, Gerhard said.

Fire crews were able to knock down the fire before it could do major damage to the building, he said. While no one is being allowed back right now, Gerhard thinks that could change with a little work,

"We're hopeful to open up part of the building once it gets some repairs," he said.

Representatives with the Red Cross were at the scene helping the people left homeless. No one was reported injured, he said.

A property management company had emailed Fisher a list of the residents who were displaced, and staff with the Nashua Soup Kitchen were also working to ensure that everyone had a warm place to sleep Saturday night, Fisher said.

"My first question was to find out if everybody was okay," said Fisher. "We are kind of early on in this process."