A fire that broke out shortly after midnight yesterday severely damaged a three-story apartment building at 3041 Frankford Ave. and forced the evacuation of its residents. The cause of the fire, which started in a second-floor unit toward the back of the building, is unknown.

Officials from the city Fire Marshal's Office were not immediately available for comment.

"It was blazing out and I was so scared," said Regenald Tyson, a next-door neighbor who described the fire as billowing out a window facing his building. "It was coming out like water."

Gray, slushy debris from wet, fallen drywall filled the front hallway of the building nearly 12 hours later. Martin Rojas-Collazo was mopping his first-floor apartment as the stench of smoke still hung in the air and pieces of his crumbled ceiling lay at his feet.

While Rojas-Collazo was sleeping with his wife and 4-month-old son, the family cat began screeching, and his wife opened the door to the living room, which she found filled with smoke. They fled to the sidewalk, where other residents were already milling about.

He had planned to celebrate Christmas with his family at his brother's home. At noontime he had not given up.

"I'm going to try to celebrate today," he said, adding that he planned later to visit his brother's house, where his wife and son had already found refuge. "I don't want this to stop me from being with my family."

As he mopped his partly flooded apartment, a fire official stopped and warned him, "We've got a wall that's going to fall on the back of this place."

It was not immediately known how many people lived in the other units.